With all due respect, I'm pretty sure coroplast is not the rubbery adhesive used to hold up the underbelly fabric stuff (which, in the OP's case, sounds more like the tarp material stuff than Coroplast).
I don't know what the adhesive is, but perhaps it is something sort of like roofing tar. I wouldn't think it's essential to replace with the same stuff, especially since it's not what's mainly holding the fabric in place. If you can scrape the old stuff off, hot melt glue might do the trick for reinstallation...or even a few staples from a staple gun.