Hi Fido, no, not in the early one piece frame. As far as I can find out they made rigid A10's from 50' to 53'. I think the first A10's were actually released late in 49' but for export only. I have also come across some references to girder fork A10's but never been able to find out if they did make any. I am not sure how the frame nos' on the rigid ones were stamped. All the dating info shows the plungers with a "S'' in the no. eg. ZA7S 0000 and the rigid ones without the S. However the rigid frame one I came across at a swap had the frame no ZA7R 7782 which would make it a 51' model. Without access to factory records its hard to work out some of this stuff. Going back to Matt's query, he has a early one piece frame and wanted to know if he could put a A10 motor in it and I think he could put a plunger type in but would need to sit the engine in the frame to be sure. It would be a lot of work and cost to find all the parts required, I've built bikes from parts and it is a lot cheaper to buy a complete bike. Brian.