If all your guns have 26" bbls, you probably don't need another with the same barrel length.
I can only assume that you ordered the 20ga. receiver. That should be perfect for 28-32" bbls. If this is a field gun, there is no reason to exceed 28" bbls. If 2" of barrel length made a big difference, I wouldn't be saying that. It doesn't. It's all about gun fit.
If you are looking for a clay target gun, your thought process might be slightly different.