I bought a LaserMax for my new Glock 20 from a dealer on GunBroker last week. Before I bid on the item, I emailed the dealer to ask if it would fit the new "finger groove" grip. He replied that the spring guide had never changed on Glock 20 models and that the one he had would fit.. Received laser yesterday. Box says LMS 1151P Serial Number 4G 02706. PRE FG/R Frame Only. For Glock 20/21. I emailed the dealer and he stands by his comments. He said I could take it to a gunsmith and he could make it work???? I'm still a little hesitant to install it. I did just go to the LaserMax website and they are listing two different models for the 20. Advice please gentlemen.