I have a 500 bought new in 1987. I was looking recently in the usual places to procure a top rail mount. One of the ads I came across for one mentioned specifically that is was for "pre 1993" Mossberg 500 models. It seemed to elude that the screws were different than those that were post 93. I'm a bit confused since I looked at probably a dozen different ones it was only mentioned by the one.
Anybody experience having an issue where this is concerned?