It depends on what you want. I would supect the 27-2 would sell for over $500, where as the 60-4 would sell for under $500. Personally, I wouldn't trade, but if the model 60 is what you want, than go for it.
The better option would be to sell the 27-2 and buy the gun you want with the money.
Shoot, I've got a LNIB 642 Pro in the FS section I'd gladly trade you for your 27.
