You can call the ladies at SASS or try reporting your post here and ask the Moderator. Just click the three dots on the top right. The moderators have been very accommodating on the CAS sight, so likely here as well.
This summer we started allowing folks to shoot our CAS match WB, allowing 5 in the mag for the 1911 and stoking the 97 for the usual 2-4 SG. Only a few do it, but seems to be well received so far.
Looking over the new rule book, the only mention I found on the mag release was about thinning years he grip to facilitate easier reach. Didn't see anything on the release itself, leading me think an extended one would indeed be illegal. 🤨