Randy Savage vs Rick The Model Martel on the WWF World Tour 1991 VHS video match took place on March 26, 1991, He was clearly getting cheered and wrestling as a face against a heel oponent competing just 2 days after Wrestlemania 7.
I had the match on the old VHS video it mentioned during the match by the commentators that this would be his last match as it was suposedly booked prior to losing at Wrestlemania 7 and he had to compete due to it already being booked by the supposed orders of Jack Tunney. It was a good match if anyone gets a chance to see it but as I said he clearly wrestled as a face during this match.
I looked up the match you're talking about, and I'm actually surprised that it was taped after WM. Don't know where they billed the match from for the World Tour video, but him and Martel had back to back matches in Vegas and Reno
Impressively for the time period though, after those tapings, the only place Savage wrestled for the next few months was in Japan on joint WWF/SWS cards.
For the OP's statement... it was a yes and no kind of thing.
Yes, after WM 7 Savage still rooted for the heels on commentary. He did not do the usual wrestler turns into a fan favorite and immediately changes everything about himself thing. It was more of a slow burn that showed exactly why Savage was able to become as great as he did. He's someone that understood the little intricacies that gave his character depth and made him seem real (wardrobe notwithstanding).
As time went on, he started identifying with the heels less and less. Part of this can be played up by being back together with Elizabeth, being happier as a result, and identifying with her way of thinking more. I'm trying to remember if this was when Piper was on the broadcast team with him though? Because one angle they did when broadcasting beside McMahon was another slow burn from the alpha face (Piper) and alpha heel (Savage) grudgingly working beside each other, to developing respect for each other, to finally becoming friends that the other could always count on. I think this was during the exact same time we're talking about here, and that Piper's influence was part of the eventual face turn too.
The no kind of thing though? Is that when he was in the ring, especially in those TV taping matches Glasgow mentioned here, there was no way in hell the fans weren't cheering for him after Mania. So in that regard, he was a babyface immediately after Mania.
The initial booking putting him against a heel like Martel right after Mania (he also fought Dibiase at those tapings) suggests the office was pushing him as a face immediately. If I had to guess, Savage was the one that pulled them back for the slow burn, and had them stop using him in North America until they were ready to bring him back full time. Because I can easily see McMahon wanting Savage to go full blown face immediately after Mania, start contradicting everything he'd say on commentary every week, and still working full time across the country... just being unadvertised.
That's almost what those TV taping matches suggest was the initial plan was, which would have been the type of thing the WWF always did. The fact that this turn was done so differently than previous ones, suggests to me at least that someone was pushing for it... and that someone was most likely the guy turning, Savage.