I bought the very Last Symmetricom SA.22C in the shop!

[Smile2016]

Z04 are likely these: nc7sz04 "TinyLogic UHS Inverter"

that's the one + datecode

[Smile2016]

Is it possible to change the factory reference crystal on the unit? 

I am planning to buy a unit that doesn't output 10Mhz it only ouput 9.8304MHz from factory.

How to check reference crystal frequency? my unit shows 60.00MHz at startup and 39.38MHz if I use "i" command .

SA22C by Symmetricom, Inc., Copyright 2006
SA22 Version 6.01C of 7/2006; Loader Version 3
Mode CN01 Flag 0000 [D04D]ok
Unit serial code is xxxxx-h, current tuning state is 6
Crystal: 60000000hz, ACMOS: 10000000.0hz, Sine: 10000000.0hz
...
r>
and with command i:

r>i
SA22C by Symmetricom, Inc., Copyright 2006
SA22 Version 6.01C of 7/2006; Loader Version 3
Mode CN01 Flag 0004
Unit serial code is xxxx-h, current tuning state is 6
Crystal: 3938700hz, ACMOS: 989680.00000000hz, Sine:989680.00000000hz
...

opened one unit , cannot directly access a physical crystal that could be exchanged anyways...