Tritium handset still glowing?

[Mrpupsi]

Purchased my 16800 sub with luminova hands, so set about finding a tritium set to replace them with.
Then purchased what I was told was a tritium handset with which the patina matched the dial almost perfectly. Had them fitted and was very happy.

Just out of curiosity, I shone my phone torch on them and low and behold, they glowed for a bit and then went out. The dial is completely dead and reacts to no light at all.

My question is, could a tritium handset still glow? Or is this likely to be a luminova handset that has been artificially patina’ed?