On the switch in front of me, it says:
D42X
3(1)/250` mu $0T85 5E4
From the datasheet at
http://www.cherrycorp.com/english/switches/miniature/pdf/D4_Series.pdf
..it has a Y5 terminal config
Digi-key has the best range I've found, lots of D42C and D42L, but no D42X-Y5
I don't know...