Josh,
If you can,I would advise you to try and find original parts if you can.Last year I purchased one of those cheap pattern headlamps (an 8" one) for my Ariel from an autojumble.
By the time i had shot blasted the very poor paint off,lead filled the front of the shell so the rim fitted nicely,removed all the spinning marks from the shell, had the awful chrome re-done on the rim ,brazed up and re-filed the slot in the shell so the reflector sat horizontal,knocked out the dent in the little instrument panel and ftted a Lucas ammeter I wish i hadnt bothered (also wish I'd looked closer befor parting with my cash).
Mike