Doubtful. You're ASSUMING that Reed has "some sort of gadget, I don't know, it's SOMETHING" powerful enough to defeat Plastic Man.
Which is foolhardy. And it's invalid in forum rules.
I can assume Superman carries Kryptonian tech to defeat Magneto (and he does use it several times in his comic). I don't know WHAT it is but it's something, right? Right....
Reed won't be able to think of something. He'd be too busy fending off a person with comparable stretching skills AND a person who can turn into anything he damn pleases. Read the rules.
"Reed will think of SOMETHING" is a cliched and broken tactic that's simply invalid on KMC forums.