I am trying to find info on these ID numbers.
I am just another 'lowly' User/Patron ...
Short Answer: 'No', it DOES NOT mean that Henrich KOCKS, does not exist.
[ Due to missing; or, more so, little information ... ]
In fact, after looking at BOTH individuals/persons:
(1) Henrich KOCKS ... ( MZR7-XKS )
(2) Henrich KOCKS ... ( MJL3-S1K )
they may even be separate and distinct (ie. different) individuals/persons, maybe not; but, possibly.
▬ has a Spouse / Wife; and, a "Source" for their Marriage.
▬ Simple search
(2) Henrich KOCKS ... ( MJL3-S1K ),
▬ has a Spouse / Wife; and, Seven (x7) Children, a "Sources" for their Children's "Christening".
That Said ...
There is a very good chance that they (either, one; or, both, separately) exist.
Sometimes ALL you can find is a "Source" (ie. Record) with just a "Name".
I consider those two (x2) individuals/persons, in some cases, have more "Sources" (ie. Documentation) than, MANY; Many; many, other individuals/persons in "Family Tree" of 'FamilySearch'.
Just my thoughts.
ps: What you have is the nature of Genealogy/Family History ▬ sometimes easy, sometimes not.
pps: Good Luck
Looked at the ID#'s both have missing information. Sent the patron an article on Research assistance.
If the information is missing for the id does that mean person doesn't exit as I can find nothing but name in all areas I looked.