I purchased a pair of Thermador SGCS365RS cooktops second hand. One
has a sticker that indicates it was converted to LP... this is
consistent with the regulator (RV47CL) which has been configured to
LP. The second cooktop has no markers indicating LP conversion and
has the same regulator configured for Natural Gas.

The jets in both are marked '140' (for 9100 BTU) and '170' (for 15k
BTU). Can someone tell me if these jets are supposed to be used with
LP or Natural Gas?

The conversion kit I found on the web (NLPKIT6) looks like it also
includes a jet holder assembly... I don't quite understand why a new
holder is needed. I couldn't find any usable markings on the jet
holders but the look similar between the two. The jets look very
similar to the naked eye. My guess is that the LP unit wasn't
completely converted but I'd really like to verify this... pointers to
an exploded parts diagram or service manual would be great!