Hello,
Yes, usually if I am there, I will install sights on HK's. Install is free if you buy the sights from us.
You know, I bet that has two magazines and our website hasn't been updated. We have very few 1 mag guns left over from the shortage.
Yes, P226 9mm magazines will work with a P228/229 9mm. They stick out slightly, but you can use an X-Grip if you want. Look at our FAQ's and it has a picture of the P226 magazine with an X-Grip.
Thank you,
Tom