Quite common to have a data card missing. Looks like you have more info than many. The metal plate is a nice one to hang on to. Not used anymore but a good piece to have.
If you want, you can order a duplicate email scan of your data card from Mercedes Classic Center in Irvine California. The recent cost is about $150. You will find contact info on this site for classic center or email/call Tom Hanson at classic Center. He’s a supporter and member here.
Your purchase looks nice. I don’t think you got a good buy, I think you got a GREAT buy. Based on the photos and your description—- You stole it at anywhere close to 39k.
Well, you found the best place to learn about the car and share your experiences.
BTW - I know Seattle area quite well - love it from May through September.
Enjoy