I see what you're thinking - the shoulder seam allowance was going to sit inside the sleeve, right? It might be possible to cartridge pleat the outside of the selleve, then sew the lining in on the under side, but I'm not sure how well that would work - my technique needs the armhole to be completely finished (folded under) before the sleeve is set in.

The sleeve, even with the curve, should fold under properly, unless your seam allowance is huge, in which case you might need to clip it, yes.