Need a weatherstripping for weathersheild sliding door

I'm not sure that we can help with this. Weather Shield makes parts for there products and their products only. If you cannot get them to supply you with this 24 year old weather stripping then maybe take a look at the generic 58-173 vinyl bubble, or even the one used on Pella doors, the 58-181. See if one of these could fit your door. I'm not certain that either can, though. There's very little wiggle room for substitution in this case.