Yea, the Classic 57s are great pickups. I had Burstbucker Pros in my ES 335 which I liked at first but after a while found a bit too hot/bright, not really ES-type sound (playing through a 1970 Fender Vibrolux).
Once I decided to change the stock pick-ups, I thought I'll try Bareknuckle Stormy Mondays and haven't regretted it! If the Classic 57s came stock with my ES I probably wouldn't have bothered changing them since I have them installed in an Epiphone 335 which I played for years and really liked.
I have to say though - quality difference of the guitars considered - that I prefer the SMs. I don't know if it is because they're unpotted or general quality, the Bareknuckles just sound outstanding.
Anyway OP, I would consider it is worth the extra dollar for ou to change the PU, the Classic 57s also work well in your guitar.