Speccy gets a lot of its info from the Windows WMI service.
For me, it also shows Unknown, even though Kingston is recorded in the Manufacturer field in the firmware.
So something is getting lost along the way.
start an elevated command prompt and type in wmic
then type memorychip
that will list all your memory details entered by the manufacturer of the firmware.
scroll right to see what is listed under Manufacturer.
or just type in memorychip get manufacturer
if that sheds no light on who made them, pull off the side cover and get a torch.