the mask looks like an early color crt, but the cabinet looks too small.

Those knobs resemble a Magnavox.

ok I take it this is not a coveted 15" roundie color :)

at 1st glance I thought it had the internal looking mask.

I had to look twice... but the contour of the mask is slightly different than a 15GP22... look at my avatar... note the bevel shape and slight curvature on the upper and lower parts of the internal mask.
jr

It looks like a Raytheon. If so, it was designed as a porthole set and I would guess the mask is a late-run modification.

That definitely was a double-take for me too... But the give-away is that the screen is too shallow and close to the front for a 15G.

Charles