That site has been around for years and several people here regularly build in that host, I would not recommend a site you can't trust. That site is also the original source of the G2 lens. I have never built a laser in a pen host, I have always used larger hosts, as far as I know you don't need anything else. I suggest you do some reading and learn more about the parts in a laser and learn what works together and what doesn't and why before you attempt to build another laser. Using a DPSS module and some non standard recycled chinese host for your first laser is just asking for trouble. If you really want a 532nm green you can just buy one for under $10. Of course they are unreliable, if you drop it it will break, they are temprature sensitive, they are sometimes DOA or fail after a short time, most times you will get a good one. I paid $11 for one that only lasted 10 days.
Alan