Side plate and triger lever pin problem

[nemra]

I very excited to join the Luger forum. Last week I finally got my first Luger. It’s 1917 Erfurt I believe Russian capture with most parts matching except magazine, sear and safety bar. At LGS it was working good but was really dirty. After disassembling and cleaning I put it back and that where problem stated. At first the trigger lever pin won’t stay in place while function checking. It will get completely out of holes after couple triggers pull. I am not sure if the pin original or not. I am not sure if the pin reversible as mine will go into the place only from one side. Also after reassembling I have to push side plate to dry fire after first trigger pull. The side plate little loose and not matching number. Also trigger lever worn on the sear side, is that normal? How can I fix the problem? Will changing trigger spring and lever pin fix the problem or not. Sorry for the long first post and thank you for your help