That sight appears to be simply this one: http://www.wgcshop.com/pcart/shopper.php?itm=GP-LS-PAQ4_srch_paq with an IR Laser diode replaceing the red laser diode that comes in it stock (and a real steel mount / hard case)
I know that the people who have purchased the above laser sight have a lot of problems with it keeping zero, and ocasionally the electronics just plainly refuse to work. It certainly does look the part though if that's what your going for.
Also, depending on how well the person did the mod, it could be reliable, or just plain crap. Not sure i'd want to risk it though.
Edit: the fact that the seller is keeping bidder's ID's a secret also has me a wee bit worried, as he may be doing that to prevent others from making the buyer aware that he/she is purchaseing an airsoft sight.