Last week I asked if a stamp (I should have said "seal") was used to indicate
Kashrut of meat.
People gave me a number of suggestions, and I'm very grateful to all who took
the time to write and share their suggestion.

I am much more knowledgeable today - and here's my summary.

First: The answer to my question about kashrut is yes: kosher meat was marked
with a seal of authentication, to indicate it is a) of a kosher animal b) has
been properly slaughtered according to ritual c) has not been tampered with.
It is a very old custom and eventually, each Shochet u Bodek had his own seal.
This seal of authentication is the type of seal mentioned by Avraham Krauss in
his response; a seal of authentication, also known in Israel as a "plomba"
(which, based on google translate, is a the Slavic word for seal). Such seals
have been in use since very very early times.
See https://en.wikipedia.org/wiki/Seal_(emblem)#Ancient_Near_East and that's
the seal discussed in the Gemara in the context of kashrut.

One of my ancestors (great grandfather's grandfather...), in Iasi Romania, was
a Shochet u Bodek (a ritual slaughterer who also confirms the meat itself is
kosher). It's clear to me that one of the things he did as part of his
occupation was putting authentication seals on meat that he confirmed as kosher.

At a certain point - as they gradually stopped using patronymics - the family's
name became "Siegler" and appears thus in some documents, and is pronounced
(I have now learned) with a soft "s". It was also spelled at times in Romania
as "Ziegler" or "Zigler". Unlike German, the Romanian "Z" does not have a "ts"
sound. Bricks, or tiles in Romanian, according to my Romanian 2nd cousin once
removed would be spelled Tzigla - (or with a T that has a little tail
underneath) - not a spelling we have ever seen for the family name. On the
other hand, a seal in Romanian is "Sigilu"

Nothing indicates that my ancestor was a maker of bricks or tiles. Nor have
any of his male descendant ever heard they were of the tribe of Levi. My
ancestor did put seals of authentication on kosher meat - it therefore seems
most reasonable to me to think that this is the reason his secular surname
became Siegler.

He was not the only shochet in Iasi who was named Siegler (or a variant
thereof). There are, to the best of my present knowledge at least two more
Siegler/Ziegler in the Iasi cemetery who were ritual slaughterer's. I have
no idea at all if they are family relatives.

Thanks again to all who took time to respond

Odeda Zlotnick

Searching:
KULIKOWER, BLASS, BOTTWIN-MELLER in Lemberg (Lwow) and Vienna;
LEISEROWITZ (LEIZEROVICI), ZIGLER (SIEGLER); COSULEANU in Iasi and Cosula
Romania ;
MENDELOWITSCH (MENDELWICZ) in Tomaszow Mazowietsky;
ZLOTNICK, GOLDBERG, SHULMAN >from Lapici (Lapich) Belarus, FEIGIN in Minsk,
Belarus