Yes, its needed. Any mods that are in the server mission are required by a user to join the server.
I just looked at the size of the 4 mods in my mods folder (I have the Blackhawk as well, although not currently in the server mission so not needed) and it comes to 9 gigs unzipped, and 4.44 gigs zipped up for all 4. Can we host a file that size on here?
link to the T-45 is here,
VNAO T-45 Goshawk - Page 12 - DCS Mods - ED Forums