Rules are made to be broken. I have always been told that you track dry unless the effect is needed for a particular piece (like a wah effect on a guitar solo). What gets printed stays on the track.
No one says you can't record reverb (or any other effects) on the way in. The only real problem is that if the effect isn't right to start with, there isn't any way to fix it other than redo the track.
Rules are made to be broken by those qualified to break them.
In this case, the "rule" - really more wise advice than a "rule" - about recording dry and applying effects later is meant as
an answer for those who have to ask the question. That is, if you're unsure enough about what you're doing to have to ask others what they do or what to do, then the best advice is to leave yourself an out by recording dry, otherwise there is too big of a risk of recording something other than what you really want and being stuck with it.
Once you are familiar enough with the situation to not to have to ask or to be unsure of the results - if it's a procedure you've already done several times and you just plain pretty much know how it's going to come out, then there's absolutely nothing wrong with recording wet out of the gate. That's not "breaking the rule", because the "rule" does not apply in that situation.
Breaking it down: If you're unsure, play it safe. If you're sure, then do it.
Getting back to the OP, if I understand your description right, the TE actually had two stages of reverb going; there was the amp reverb first, and then that was being further fed into a stereo reverb on an aux send.
What that says to me is that the amp reverb was a "sound" he knew he wanted; i.e. he wanted the sound of an electric guitar sent through an amp reverb, and then he wanted to take that sound and "place it in the room" and the mix with the stereo reverb. Two different effects for two different reasons being used simultaneously.
If that's the case, then the amp reverb was, as Rocket put it "necessary for the piece"; i.e. the engineer knew he needed/wanted that sfx sound no matter what,
as a sound, so there were no "rules" broken. In fact, he then ran it through the stereo reverb on an FX aux send, allowing him to record/mix the stereo reverb separately from the guitar, leaving him that out, that flexibility called for by "the rule", so he really was playing by "the rule" all along.
G.