There is high potential for damage to the chainstay tubes and almost certain damage to the paint using a kickstand in a bike with no kickstand plate. Here is the chainstay of an '85 Stumpjumper I bought thru eBay:





It had a kickstand and I bid on it hoping for minimal damage and fortunately for me it was only paint damage.

I have seen more severely damaged seat stays here and on eBay and here are particular examples:

Here is one from an eBay auction a while back of an 84 Stumpjumper:




Here are 2 from pics posted by Juls (forum member here) of a DB Ridgerunner:





Here is a link to a blog with a recent article relevant to this discussion: http://www.tamiasoutside.com/2013/04...man_pletscher/