As the Gulfstream editor for Scramble I'm following this with interest as well. If you come across the previous identity for the JCG G550, please post it here!
02/16/2021:
1-) The JCG G550 (JA502A) was still parked outside of the service center, although it appears to have been rotated 180 degrees after last week. I was informed that it's most likely serial 5616 (N516GA) and it will be ferried out to the Netherlands for modifications in the coming weeks.
2-) US Navy P-8A Poseidon (168434) did several touch and gos
3-) US Navy C-37B (166376) made a quick pit stop and subsequently departed less than an hour later
4-) One of the local 165th AW C-130s (93-1561) arrived while another aircraft (didn't get the reg) departed for some circuits at Hunter
5-) A USAF C-37 is at the service center, although I drove by too quickly to note the registration and the specific variant (A or B).
6-) An Algerian Government G-IV(SP) (7T-VPS) was seen partially sticking out of a hangar at the service center
7-) N584GA, the green G550 waiting for conversion into an MC-55, is still outside of the modifications hangar after a few weeks or so
8-) A Turkish Government G-IV has been at the service center for a while. I'm almost certain that this is TC-GVB, which I managed to read off in late December.
Noted this morning were the following TAW-5 T6Bs
166025/025/167/172/177/214/220/243 with TH57C (162025)/E-61
Also in was C17A 93-0601 bk/yl 758AS/AFRC
The SD F16s went home at some point last week although 89-2086 came back on Thursday for a night stop and departed again Friday as Lobo 41
02/25/2021:
1-) Israeli G550 CAEW (N552GD) was parked in front of the mods hangar, replacing N584GA
2-) USAF C-37B (09-0525, if I'm not mistaken) was at the service center