Time to be the devils advocate.
I have bought brand spanking new , still in original BSA wrappings , parts that did not fit on more than one occasion.
Been playing with BSA's for 50 years now and there is a big difference between what is considered as proper fitting in 2017 and proper fitting in 1962.
Add to that BSA used the same forgings and casting for a lot of different bikes so just because your part has the "right" blank number on it is no guarantee that it was machined to fit your bike.
Forks were regularly swapped between bikes, both by BSA in order to meet a shipping deadline and by end users because the wrong ones were cheaper.
So unless that bike has been in your possession since new there is no guarantee that any single part on it now is what was on it when it left the factory and even then it could have been the wrong part.
I have run into the "funny fitting shroud " problem on more than on occasion and the solution was to cup your hand and gently bend the ear in and if necessary then twist the mouning hole out.
We even had a tool for doing this , a piece of dowel with a chair leg stud on each end a couple of large hard plastic washers and an oversized pair of wing nuts.
Once the dowel was in place you stood in front of the bike and "applied corrective force " to get everything lined up and true to the frame.
I am yet to see an original set of shrouds that have not rubbed through on one side because they did not sit strait on the fork legs from new and the same goes for the chromed fork seal holders which is why I use stainless ones as the scratches can just be polished out.
Then you have things like damage in the post.
I got Barry Bligh to make me up a set of headder pipes for my OIF A 65, with a custom bend so you could get to the primary adjuster without removing the pipe and the mufflers sat at the same height off the ground at the end, Which IS SOMETHING THAT BSA's RARELY EVER DID, BRAND NEW ON THE SHOWROOM FLOOR.
He made them up on my bike while I was down there and then bent a second set for my other bike and a third for refference .
When others saw my bike they wanted a set as well and he did several more .
Of these only 1 actually fitted properly.
Why ?
Well the truck carries 24 tons of mail and heavy packages go on the bottom.
So unless you paid for them to be sent in a steel or wooden box, don't expect that the condition you got them in was the condition that they were posted in and if the two ears had different angles off the fork axis this would suggest damage in transit as one would imagine they were made in the same jig & were the same angle when they left the factory.
Now I am not discounting that they might not have been the best reproduction in the first place, but clowns like me just make them fit & if the batch was only 48 pair then good chance 20 of them are yet to be fitted and the rest went to old timers who don't expect any thing to ever align properly and were just happy that they could get something to fill the gap without haveing it made bespoke for around a grand a pair which was the case not so long ago. So no one complained.
No retailer checks parts for fit before they are despatched and even fewer check them for fit if they have them made .
And if you stop to think about it BBB would either need a $ 3,000,000 computer operated profile checker + all of the original dimensional drawings programmed into it and that would add another ? 20 to each part , if not more. Or 150,000 go -no go gauges to check all stock plus a warehouse double the size to keep them all in, 10 or so more staff to check each & every item into stock which would double the purchase price to you.
I have bought the absolute wrong part from many suppliers simply because it was put in the wrong bin.
IF you really must have exactly right parts then I am fairly sure Mike Riley still has some NOS shrouds in his shed but they come at original BSA NOS carefully checked parts prices, around $ 500 Aus + freight