Professional REMF

I just got this button from GG&G, but I didn't get a new roll pin in the package. Is it possible to safely use the original roll pin, or do I need to find another?

"Those who can make you believe absurdities can make you commit atrocities." - Voltaire

Is anyone in possession of an extra magazine spring seal ring and willing to trade it for an extra (unused, new) mag spring for an M4? I'm getting tired of buying one part at a time...hahaha. (Seriously, I have reduced hand strength due to breaking my back some years ago in the AF - that's why I'm "Professional REMF": I was a Transportation NCOIC - anyway, the seal ring has gone buh-bye, and I'm trying to get out of another $45 expenditure. THX in advance.