Well that sounds promising! In my experience, I've never really liked that cold start seal in the first place.
It's on the high vacuum side.
It's a relatively thin, flimsy flange that is almost always bent from the force of the bolts that hold it down.
It's a high surface area to the number of bolts that hold it down, and those bolts are far from the center on those flimsy wings.
So if I had to have a cold start valve (which I'm not sure you do), I would slather that gasket up on both sides with silicone sealer. There's no way I would ever trust it put in completely dry.
But that aside... Being in Dallas, when do you ever, ever, ever get weather cold enough to even really need a cold start valve? It's not like you guys ever get temps below freezing, let alone into the 20's*. I've removed my cold start valve and capped off the hole and haven't looked back. I think you could do the same.
But (and I'm not judging) if you do want to keep it, for whatever reason, I would absolutely use some gasket sealer on that thing. If you got 13 with it blocked off, it's clear that if it's not leaking air, you're readings should be just about perfect.
And don't worry about the egg at all!
* Except for a week ago, right?