Unfortunately no. Best bet is to buy a new band, and sell the old one here in the marketplace or something.
If you were responding to me, I have a different opinion based on my selling several watches all on different websites, based on who was paying most.
In all cases, you had to select the exact configuration originally sold by Apple. That meant the exact watch model paired with the specific band originally sold with the watch. I'm not aware of any way to select a custom watch and band combination.
Of course, if you don't have any intention to sell your old watches this way, then my opinion would not be relevant.
ADDED: I think your "unfortunately no" applied to the OP, not my comment, but still offering my opinion.