Maybe so, but be warned if you special order ports with 10 mm glass it
may take 5 months to arrive from China, have gaskets that do not seal
completely, and holes for through bolting that do not line up.
Oh................ And then NFM says you are wrong and do not tell your
story or they will sue you.
Could be the person handling my special order was having a bad day.

Personally, I think the AMERICAN made Spartan ports are super and only
25 bucks more. My advice: You may be fine if inspecting a stock NFM
port closely and then buy it. Do not trust NFM with non-refundable
special orders. They hold all the cards......... your credit card.
Bob