Probably have the end cap you need sitting in my garage at the moment.
None the less, Grainger Parts is different than Graniger in general. McMaster Carr in E-Mail is similar to Granger Parts in getting stuff. Two excellent sources in getting anything under the sun not advertised. When I speak of anything, both companies can get about anything in a timely way and cost effective way. I find both sources for anything I want very useful.
Contact either or and talk direct in getting what ever part you need at a reasonable price. Intent with both companies is to help not
mark up
thru the roof.
Now more a question of cost effectiveness. Wouldn't it be more cost effective given an exit light to replace the
fixture rather than replace the part?
Further note on soldering on...
etc in modifying the gear... urr, at best safe enough, at worst... you no doubt already know this. Probably will have been better off replacing the
fixture with something that has a UL listing your modified
fixture no longer has than modifying the gear that even if absolutely correct will always be of in question. Yes it might be a good repair, on the other
hand you have to balance both cost effective with what risk for a perminant
fixture you are risking lives with or in some future problem you might become suspect even if safe for having casused.
Exit light, salvage what parts you can and replace. Given spare parts in future items replace as safe and work from there until they are all replaced. Much more time efficient and cost effective in the long run I would opinion.