That is correct. Altiums uses Compound Document Files like MS Office does. Inside this structures there is a thing called FileHeader and inside that Altium stores all most of its stuff in a text format.
The format looks like this: |value=N|
As you can see, they use | as seperators and the only other symbols they use that I am aware of are = and . (a dot which they use for things like LOCATION.Y=10).
You could try these two Symbols and see if they work but I think they will work just fine.
P.S:
Here is an article about the file format where you can see it:
https://hackaday.io/post/10390I also tried to reverse engineer the whole thing once (PCBLib files, not schematics) but I wasn't able to do it completely because there are some binary values in there which I just couldn't figure out what they do)