Stop in for a cup of coffee

WV64Signet said
The gaskets inside were all blue ones which I understand are not the original (??)

I beleive that is true but don't know that for certain.
The last carb I bought NIB was a 3310-3 in 1989. At that time new Holleys came with tan gaskets and I dont recall blue gaskets for sale until a couple years later.

WV64Signet said
Power valve and a couple other places had double gaskets.

Or the gasket split when removed. I find that is really common.

WV64Signet said
The screws on the secondary metering body were barely finger tight.

The secondary metering body plate is missing completely....

I spy

a metering plate.
Surprised it didn't leak externally without the plate. Some plates also have a sheetmetal gasket of sorts.

WV64Signet said
So if the secondary diaphragm looked to be messed up...perhaps not allowing the secondaries to kick in...would that explain how fouled up those butterflies were and why the back half of the intake had so much more buildup compared to the front?

Maybe.
Fuel only flows to the boosters when the air velocity is high enough.
Fuel flows to the transfer slots when they see manifold vacuum.
The secondary transfer slots are high up but slightly opening hte secondary throttles would expose them.

edit: without the the plate