You said why weighing them is likely a waste of effort and time both.
That would not tell you much if anything.
Anyone that reshrinks a well worn box set is not beyond putting blank papers into the box instead of the true contents.
And how do you KNOW that store did the reshrink job?
IF They did do it, then they likely purchased someone else's boxes and reshrinked them for sale in the shop.
Even if they did, did they KNOW What the contents were supposed to be?
You also said you would like your listing to be accurate.
Please tell us how you plan to do that?
Do you know what is inside?
I mean other than what was SUPPOSED To be inside...
HOW can you possibly do that with something that was RESHRINKED!
PLUS you might find some treasure that does not belong...
Like a copy of Dwarven Glory some idiot stuffed into one of them...
I saw your ad, and honestly I would rip that reshrink off them both.
I might even make a movie of it and post it for the shrink junkies to weep over...
It is obvious both boxes have a good bit of wear on them.
Might as well confirm the contents and then sell them as they are with all openness.
At least that would be my move.