There is a new old stock secondary air system valve,
GM 90466214, on ebay at the moment. It's grubby looking so it hasn't sold, so the seller has relisted it several times. Now starting at £15.00 + postage @ £3.75. I'd 'make an offer' and see what happens. Can't be worse than one from a scrapper. If you do buy the valve then blow through the vacuum ports with compressed air.
This electric solenoid valve switches vacuum to actuate the secondary air injection valve that sits to it's left in your photo (in the other thread). This injection valve is not the HBV heater bypass valve.
The injection valve inlet hose connects to a one way (aka check) valve that is screwed onto a metal pipe that is bracketed to the engine. V6 check valves are made by Pierburg, yours might be as well. This pipe in turn will connect to the secondary air pump. When the air pump is running and the solenoid activated vacuum will open the secondary air injection valve and air pumps into the exhaust ports. This should only happen when the engine is cold.
So you don't want the secondary air injection valve to be failed or otherwise stuck open.