Trunk lid supports
 

I've posted elsewhere, but no luck yet. One trunk lid support is missing and the other on the way out on my 2003 CTS. Local NAPA and many online vendors show that there were first and second editions of this strut, one being 11.1 inches long and the other 11 1/2.
The sequence number in the VIN is 155890, but I can't seem to find any information on when the switch was made. A Compnine build sheet shows that the build date is unknown.
Anyone know of a way to determine which strut I need for this trunk?

In case anyone is following this or has a similar issue, I think I've found the solution. Removed the trunk lid support. Found what looked like a part number to me. 15911948. Googled it and you can find them all over the place online.
Local parts housed wanted from $29 to high $30s each. I found GM parts from Rydell Chevrolet, Buick. GMC, Cadillac for $11.84 each and ordered a pair.

This forum doesn't get a whole lot of traffic, does it?