Not really, they didn't do anything really stupid to that circuit. The "pull boost" uses 1/2 the reverb tube as a boost, and it doesn't sound great, but if you leave it pushed in it's out of circuit. I compared my 81 to my 68, back to back and could NOT hear a difference, even down to the tick from the term circuit.
Back in about 1994, I purchased a 1974 Deluxe Reverb for $450.... It replaced my Dad's old 1971 DR that I had been using and was afraid something would happen to it and didn't want to hurt my Dad's amp. I later found out that my Dad's amp was a 1969 Deluxe Reverb.....Silverface cosmetics with all Blackface guts.
From what I can remember, the '74 had quite a bit more mids and less top end. I remember having to turn the treble up from where I normally ran my Dad's.....But, my Dad's '69 also had a '60s Vox Alnico (pre-Celestion Blue) in it and the '74 had a stock Fender speaker which is probably safe to say was a good 85-95% of the tone difference.
[EDIT] I guess you asked what for thoughts on the amp...... I really liked it! Not sure if I liked it because it was "my" amp, or because I didn't know better.... But I used it at every shoe (2x per week almost every week) up until about 2004, when I traded it for a 1978 Twin (big mistake), that I later traded for a Line 6 POD XT Live (even bigger mistake) to the same guy I got the Deluxe from 10 years prior.
So I pulled the trigger on a 1979 Deluxe Reverb. Got it for $750. She's got a few bumps, but nothing major and everything seems to work great. I just pulled the chassis and there was a tech signature with the word "Blackfaced 12/2013" on it. So...I'm going to post some picks on another thread and see if I can get some more details on if this was truly blackfaced.