Spine is important, no matter what style bow you're shooting. Critical, in fact. If you don't have the right spine, you can get by with field points if you're reasonably close , but it must be exactly right to shoot broadhead arrows well. His claim is bogus as you suspected, but the arrows may shoot well, because recurve bows need considerably more spine than the draw weight number. Arrow spine was originally based on self bows, and bows with more advanced designs need more spine than self bows at the same draw weight.