Is this 13 Loth?

[AllSeasons]

I came across these spoons that are scarce in marks, but do have a 13 marked on them (last image). There are no maker's marks. I'm not sure if these marks denote 13 Loth, or the silver-plate number, or if they mean anything at all. Is there any way to tell in this case?

The images are below. Thank you in advance.

[Bahner]

Hello, would be surprised if this did NOT mean 13 Lot. Only a scientific examination of the fineness would tell everything. Regards, Bahner

[AllSeasons]

Hello, would be surprised if this did NOT mean 13 Lot. Only a scientific examination of the fineness would tell everything. Regards, Bahner

Thank you! The seller said they did a scratch test and it tested positive for silver. However, I do not believe they did a nitric acid test by filing into the spoons. Can I safely assume that these are 812 silver?

[AG2012]

Scratch test on stone is not reliable at all. False positive result from silver plated layer.
Only deep filing where it cannot be seen, then polish.
Regards

[AllSeasons]

Scratch test on stone is not reliable at all. False positive result from silver plated layer.
Only deep filing where it cannot be seen, then polish.
Regards

Thank you. Yes, that's my understanding, as well. I was hoping that together with Bahner's assessment on the mark, a scratch test would be sufficient.