I'd go with the consecutive number pistol, you can always pick up the other model at a later time. I have several consecutive sets, all but one by accident. Only one was purchased as a consecutive set, they were Winchester WIN-13 Garands. The others were by chance, where I recognized the serial of a rifle or pistol for sale as being close to one I owned, checked and found to be consecutive, then begged or bid furiously to bring them home. The hunt is part of the fun, the accidental discovery is even cooler. Go for it.