Paulo,
It looks like you have a very nice car there - certainly based only on the pictures you presented. There is this decision moment: do I keep what is there with all the traces of history or do I restore the car to "new" condition as per the factory specs (or to the colours I like - some prefer that).
I think an important input to this decision may be if someone looks at the whole car and provides you advise of what is and what is already not an original and gives you a full scope of "work to be done" if you wanted the car to be original or restored as original. I think this is an important parameter.
For instance:
- carpets indeed may not be as per factory and are (in my view only) spoiled a bit by the speakers. Yes, there are companies in Europe who make very good, original-like carpets. So you may have new carpets.
- then you will see how your seats look like when the new carpets are there and you would decide if you like it or not (this is what happens when you put part of the interior new - the other parts just may look worse).
- seats - they look ok, but someone would need to verify if these are correct seats for your car (I am not saying they are not!), i.e. 230SL 1966. I may be totally wrong, but they seem to me after /8 seats - but again, that can be wrong.
- there are some small things I see that would need to be looked at and decided - some work in trunk side panels, I do not know how your spare wheel is to be attached - left side upright or right side level, if right side level - something may be missing there
Again: depending if you want your car with patine, but original, restored to specs original-like or just very good looking or just decent looking driver - all of these options will require different investments and efforts. And we are talking just interior here, while there may be work to be done on chassis or drive train.
If I were you, I would have shown the car to someone with knowledge about these cars and discuss the above options. I have nobody like that where I am, but you have experts there in the UK (e.g. Collin Ferns).
As for the carpet suppliers the UK Fellow Members will come with advise, I am sure. For Europe - e.g. KHM, Eurotop. For trunk mat - the original was, on the left and center, a grey ribbed rubber mat, PN A1136840104 (as of chassis number 042 007205) and under the spare wheel, on the right a rubber pad PN A1136840404, replaced by A1136840604. They are NLA in Mercedes, so either you need to find the originals on e-bay or look at shops such as e.g. SLS for reproductions.