I'm glad to hear that you've got your amp up and running, and I'm sorry to hear that you had problems along the way that forced you to reach out to a repair facility. The type of cap job that you're talking about isn't at all hard. It's something that anyone with decent soldering skills should be able to do on his own if they have all the right information.
Once upon a time I had written a complete tutorial about re-capping the low/mid rail caps on the 1.5 type amps, so that anyone with a soldering iron could do this type of repair at home. The tutorial showed the complete steps for how to do the repair, with photographic documentation of every step. Unfortunately, all of my posts got deleted from the other site when a half-brained idiot decided to ban me and purge all of the evidence that I had ever existed there. As a result, the entire tutorial got erased. Gone forever. That's too bad, as the tutorial included comparisons of the different caps that are available for the job, and included guidance about which caps were good for the job and which caps were not so good. At one point in that thread, someone joined-in who had fabricated a replacement board that he planned on selling. It sounds similar to the one you're describing. In the thread we had discussed what types of ratings were desired for the caps for this application, and the caps that were being offered in that kit at that time were not up to par. I don't know if that' s the same kit that you're referring to or something different, and now that the information has been purged from the other site, there's no way to know.
Regarding your amp, the good news is that you've got the low/mid supply rails working again. You don't ever have to worry about those caps again unless their should fail, and if they should fail, you've got a repair path in place. The bad news is that your amp has got a whole lot of other caps in there that are pretty darned old, and are likely to be out of spec. The amp would benefit from having them replaced. While most people focus on the PSU rail caps, there are other caps that are prone to fail in subtle ways, and those caps are going to need to be replaced as well. What most people don't think about is that with old amps, the aged caps in the protection circuit are prone to fail, and when the protection circuit fails you're really in trouble. That's when amps blow up.
Being the guy who started the whole Carver-recapping craze, I agree with the recommendation that it would be best to recap the entire amp when you have a chance. Until then, congrats on getting your amp working again, and enjoy the music!
Carver Preamps: C-1, C-2, BillD's JVD-modded C-4000, C-9
Carver Amplifiers: BillD's C-500, M-1.5t (4) PM-1.5 (4) M-500t (2)
Repair/Restoration/Upgrade expert for all of these components.