You said 15 years ago, so which docter were you referring to? and more importantly, how was it mounted? They didn't do sight cuts or plates back then. Huge difference. How does it compare to the Holosun K series or even RMRcc?
Either way, at the end of the day I'm not sure why someone would have an issue concealing one with a good holster or especially AIWB. Hell, there's a very large man that sells great holsters here in Oklahoma that carries a full size platform AIWB with no issues and makes videos about it. So anything is possible. I have a Holosun K on a 365xl and either AIWB or @ 3:00 I have no issues. Seemingly a LOT of people carry larger platform with a RDS with no issues.
Not trying to be d!ck here, but there was at least one guy with a milled slide running a Trijicon MRDS optic on a Glock as far back as 2008.