I have some Hittite dies from 1997 HMC129. the fets on the die appear to a lot smaller than the 2007 die parts.
they are both HMC129 parts. I can not find data on the 1997 part. are they interchangeable?
Firstly if the HMC129 is going to be used for a new design then please be aware that this part is not recommended for new designs.
The 2 die are different due to a process change. The performance between the 2 die should be similar (isolation). There might be better conversion gain on the 2007 die (1-2dB difference) than the 1997 die.