measure your track, compare it to makers that you can find, then buy your slides from them. Only the width, and thickness of the track itself is critical the upright/base doesn't matter really. Yours, with that recessed center, means that you'd want to go with a screw type, not spring loaded.
Can you measure the slide itself?
On one of my boats there was a box of parts, and I ended up with a couple slides that don't fit anything I have. They're wide enough, but made for a thicker track.
Here are the dims for schaefer tracks, which may allow you to match yours up and determine if the slides will work:
APS - Schaefer T-Track Eye Slide Cars