M2 will only fit HK.
Go to this thread and U will see a store link that sells the laser - it is expensive, however. But it fits the closed rail.
Another place for Walther products
Also, for lights, U may wanna buy an adapter to convert the old rail to a standard rail (like the Hk guys do a lot). Then, your light options would open up. The lights for the old rail cost way too much.
I lost the link on where to buy that adapter - but if Uncut sees this thread, I'll be t he can give U the link. All my frames are the new style, so I haven't had to worry about that.