I'll have to get back to you on that. I made great (novice) gains before I started TRT, unfortunately just as I came on I sustained an injury that has kept me very limited in the gym. Currently doing aggressive rehab with a great chiropractor and can't wait to make full use of my new high T.
One thing I notice though, even with limited training (and consciously eating less since I'm training less) I maintain very easily. Before TRT, if I was out of the gym for 2 weeks my gains would start to evaporate. These days, when I can lift, I'm just strong as I was before the injury and sometimes stronger--and I lose very little muscle and gain no fat regardless. My body is at a new set point. That part is great.
But in general, I'd guess everyone should make some gains if their protocol is sound. Not crazy cycle gains, but solid gains that would have come more slowly (or not at all) being low T.