Leaving Fuel pressure test adapter in permantly,Can the schrader valve withstand fuel deteriation?

[redding]

Intriguing! I recently installed a reconditioned fuel injector pod in my truck along with that very same adaptor. I've had it on the shelf for at least seven years. So far, no leaks but I am curious as to how long it will hold up.

its the sealing rubber o rings in the valve stem core that bring a bit of concern to me,the rest seems fine,I would fit it with a metal cap when I do

 

[SNCTMPL]

I left mine on for years without problems, in fact it is still on it, although just sitting on a shelf for the time being.
I do have a cap on it.