Nice! No the stock stems offer zero cooling, they are plain short stems, great for feeling the heat and vapor and tasting the herb, perfect for learning to control Milaana and how it heats up though I never use them anymore myself (just backwards as WPA in my TM) if you can find xl8r stems those are better, but I think even better would be to get vigreux cooling stems from @508phineas on Instagram btw
No it does not come with one, and it is actually pretty tough to find one, Mi3 glass is 19/19 so to get a proper WPA you will need to order a custom male to male adapter where the joint is cut down to 19mm length... Possible some 19/22 joints could fit, which is more standard, with variance in glass, however it is risky need to make sure proper fit...
Alternatively you could do a Delta 3D SonG adapter or other such silicone adapter, or other mods to connect standard stems to other glass.