Originally posted by FL81 I know gw-3 is ment for gr2 but my question whatever old version gw-1 and gh1 hood will work with gr 2 2015?
No, the older extension tube will not work on the GR or GR2 - the thread is smaller. You need the newest hood. It's possible to use the older conversion lenses but you'll get some very soft edges and vignetting at best. I occasionally use the GT-1 mounted on my GR via GH-3 and a step-down ring - it's fun to use but is definitely noticeable (extreme softness around the edges) at wider apertures.
Also see this thread.
https://www.pentaxforums.com/forums/161-ricoh-gr/254240-50mm-conversion-lens-ricoh-gr.html