That doesn't look much different from my police trade-in 92G.
I wouldn't worry about it too much. It's not like the slide is going to wear all the way through the frame or otherwise compromise the structural integrity of the gun.
The one question I would consider is how you lube the gun. A light viscosity oil like what you get from anything in an aerosol can is, at best, less than ideal for frame rails.
The general rule many follow is to use oil on anything that pivots or rotates and to use grease on anything that slides.
The canned aerosol stuff is okay on FCG parts. For frame rails (and the buffer assembly, BCG, and CH on my ARs), I like to use the high temperature, multi-purpose grease found in the automotive section at Walmart. It's really cheap, it's slick, and a little goes a long way.