I've been told that the LPST mentioned needs a chip installed in the aircraft circuitry to uniquely identify the aircraft (for charging purposes??).
A Mode S transponder is indeed programmed with a unique number which decodes to your tail number.
However, Mode S cannot be used for enroute charges because of unsufficient radar coverage (in the context of normal low-level VFR flight). This is a common myth going around this business.
There is no "chip" as such; a transponder is full of chips
The programming of the Mode S code is trivial; you can do it yourself (although you aren't supposed to
).