I've had many sets of TCCD, here's a summary:

set1:
2x512mb OCZ rev2, 1 stick does 320 2,5-3-3-7 1T @ 3.1V the other one does a very dissapointing 270 same timings/voltage.
Most likely these were 431 chips. (sold)

set2:
Gskill 1GBLE 0437, 1 stick does 300 2,5-3-3-7 1T @2.8V the other one throws a few errors now and then in memtest at 275. (RMA'd)

set3:
Gskill 1GBLE 0431, 1 stick does 300 2,5-3-3-7 1T @3.0V the other one gives one error every test at the same address all the time (RMA'd)

set4:
Gskill 1GBLE 0437, 1 stick gives an occasional error at 275 2,5-3-3-7 1T at any voltage between 2.6 an 2.9V the other stick throws hundereds of errors at 275 2,5-3-3-7 1T (RMA'd)

set5:
Gskill 1GBLE 0440, 1 stick does 300 2,5-3-3-7 1T @2.8V the other one does 305 same volts and timings.
No need to RMA this set.

So, i don't think you have to look for the magic 0437 chips TBH.