Yes, most commercial peaches are grafted/budded, but as a rule, peach seedlings come fairly true to the parent type - 75% or more would be anticipated to produce fruit not significantly different from that of the 'mother' tree. Seedling peaches will probably fruit pretty quickly - wouldn't be surprised to see 'em bearing in as few as 5-7 years.
Most fruit trees and some other varieties are for lack of a better word are "freaks of nature" and will not reproduce true offspring from their own seed so they must be grafted onto a rootstock. For instance, apples are normally grafted to a crabapple tree. In the case of peaches, the seedling from a peach seed will go back to its original "wild self". The wild peaches are much smaller but are much more resistant to disease - in most cases. These seedlings are used to graft the cultivars to. What's interesting is you can mess around with different type root stocks in the same family and make super dwarf trees. One of my favorites is a super dwarf elberta peach that won't get over chest high. Makes for easy picking and it does bear well. BTW- I got one apple tree with 5 varieties on it. Just wish I could remember what is what.
I've heard that the seeds need to be frozen before they are planted - any truth to that?
Jogeephus, thanks - I appreciate the information. I also plan to be back in Colorado for the next "peach season". It became obvious that I didn't buy enough when my wife found them. Darn "peach breath" anyway!
Plant them. Most likely they will not bare fruit but will put on flowers which will draw in bees which are good for your garden. The more bees you can draw in the better. You never know though, my neighbor has a lovely peach tree that gives off about two bushels a year and it was grown out of her compost pile from discarded pits.