GlenB,

Here's a couple of reasons to go ahead now, in addition to the possibility of spawning:

1) by stocking forage now, they get fully acclimated/adjusted to your pond and are much better able to defend themselves when the predators are stocked later. Stocking them at the same time leads to mass slaughter...thats my opinion, not necessarily backed by scientific data and
2) fish prices are much better now than in the spring when everyone else is buying.