A "VAM" hard decision to make.

I recently received a box full of Morgan Dollars from an estate sale I went to. I list some of the coins I did not need for sets on Ebay, which did not sell. The highest bidder just missed the reserve price, but contacted me to find out the price. This particular coin is a 1921 P VAM 3T. (Thanks to the high bidder for identifying for me) I am not very familiar with the whole VAM system but I looked up the coin of VAM World and found this information:

3T IV 1 ? D2a (Die Breaks 1 & Wing Tip) (189) I-3 R-6

with the following:

Obverse IV

Eyelash missing, hairlines more pronounced, LIBERTY letters different.

Reverse D2

16 berries in wreath.

I-3 = Significant die variety with general interest to variety collectors.

R-6 = Very Rare (Several Hundred)

This coin has a blueish-green hue and sharp details. With there only being several hundred known, should I slab it for preservation, or release it back into the market?