Glad you liked the article. As that Sako TRG-22 is used as a test bed to test optics your Accu-Shot has probably appeared in a number of articles you are unaware of. Feel free to use the picture on your website.
As to your questions, yes all the TRG-22 and TRG-42 stocks are basically the same. I cannot comment on the TRG-21/41 series, but I expect them to be similar. No modifications were made to mount the monopod.