Yup, if it comes fully assembled like the picture shows, you should be able to. *edit: meaning, yes, it's exactly as easy as you think it is to install if it is fully assembled. Note that some gens of KJW M9's have adjustable hop ups - the current ones do, and the current ones are the ones with colourful reinforced loading muzzles, like in the Cansoft KJW M9*
Email buyairsoft if you want it (at that price), ask if it is fully assembled.
The bracketed section is just my bias, not to mention that I buy parts from KJW all the time for cheap and highly functional TM replacements, since it's a pain in the butt to order parts from TM directly, lol.