Yea, lol that would be my thought
But yea, I too never heard of a dealer doing a UOA, but you never know, as oil analysis "catches on" it may/could happen.....then again, there is the other side of the spectrum, a used oil analysis can't tell you "everything" about the oil in a vehicle......but can give you a good opinion of it anyways.
But yea, you could try returning them to WM for store credit, if it's oil that your WM stocks, AND as long as the neckbands or foil seals (if applicable, they will check) have not been broken or punctured. Just tell them you bought the wrong oil, or too much oil, etc and see what they'll do.
Here's the kicker though, since you don't have a receipt, at WM you're only allowed 3 no-receipt returns per year or something like that....so you want to return as much of it as possible, at the same time
But, not too much, that they would be going "hmm, that's really a lot of oil to be buying on accident".
No idea if the 3 returns per year is company wide, or just per store....I know they'll ask for your ID so it's tied to your ID, wouldn't doubt that it's company-wide.
Also, I had a thought, where is this truck calling for 5W-30 "year round"? per the oil filler cap? or the manual?
I know in two of my previous vehicles, my 07 Kia Rio had 5W-20 stamped on the oil filler cap, BUT the manual had noted that if the ambient temperature was between -20 and 120 degrees, 5W-20, OR 5W-30 were compatible, OR between 0 and 120+ - 10W-30 was acceptable.
So I could "safely" use 5-20 5-30 and 10-30 in the vehicle without fear of voiding any warranties.
Though my Optima manual had a wider selection of weights available, the 5-20,5-30, 10-30 and 15-40 even....but couldn't see using that heavy of an oil.....even if the manual stated it's "OK" lol...