It's a Sunn 200S, probably a 1968 or very early 1969. The grill cloth is correct. They only
came OEM with JBL D140F's unless they were custom ordered, and that was a very small percentage.
Shame it got away, it looked extremely clean for a 45 year old cab.
If those are the factory JBL's and they're healthy, it's worth considerably
more than $50.