Hi,
Lozbass bought his gp12smx from me as a sleeve mounted amp so unfortunately there are no rack ears with it, but you could always make your own,
I made some from a small sheet of 2.5mm mild steel Measured,cut, bent, drilled & sprayed black, they did the buissness in my rack setup.
Trace gear is the best in my opinion, i only sold loz my 250smx head as it was only used for practice in the bedroom, i am now looking for a little practice amp, i still use my ah600smx head for live gigs & would never sell it, it sounds awsome & i have tried Eden,Swr,Ampeg & none of those come close