Don't think so Pookey, unless Speed is referring to the B737-100/200s (I really am not sure about the Heat Exchangers on those Aircraft), he is incorrect.
The 737-Classics have identical Heat Exchangers in the left & right wing tanks.
The Left Main tank is not "traditionally" used for fuel temp readings.
The 737s which have an equal amt of exchangers for both tanks use the left. The B757 which uses 3 ht exh (2 in lt tank) use the reading from the right tank (coldest tank). The B767 and B777 are opposite of the 757 and use the temp from the coldest tank, in this case being the left tanks.