Yes.
Non Lumia (OEM) flashing, devices, and FFUs are different.
With that said...
The open market FFU is different as far as the PLAT ID in the FFU and I did confirm. My open market model IDOL 4s phone Plat ID is ALCATEL.8996.IDOL4S identified from a xml under an Image Update folder. Not sure why this is but it is. I have not figured out how to mount the PLAT partition from my phone as an MTP mount or some other way. And that is the only way it could be changed. It looks like it resides in a SMBIOS.CFG file under PLAT:\SMBIOS\SMBIOS.CFG
I confirmed a dump from the FFUs below:
TMOUS PLAT ID identified in the FFU below:
Number of partitions found 34
Warning: RKH of SBL1 is missing from the FFU. Flashing the FFU may result non-booting device.
Warning: RKH of UEFI is missing from the FFU. Flashing the FFU may result non-booting device.
Platform ID: ALCATEL.8996.IDOL4S
Hi. index sector 40955648
Computing integrity of FFU. Please wait...
.............
FFU integrity OK.
Open Market FFU PLAT ID identified in the FFU below:
Number of partitions found 34
Warning: RKH of SBL1 is missing from the FFU. Flashing the FFU may result non-booting device.
Warning: RKH of UEFI is missing from the FFU. Flashing the FFU may result non-booting device.
Platform ID: ALCATEL.8996.IDOL4S.NA
Hi. index sector 40955648
Computing integrity of FFU. Please wait...
...............
FFU integrity OK.
Now, what does not make sense is that the PLAT partition extracted from the FFU of the OPEN market device is also listed with PLAT ID info as ALCATEL.8996.IDOL4S. I think the OEM really messed up here honestly. It is a hex file and you can see it below. I am not sure if the FFUs are signed this way on purpose and the PLAT info was never updated or if something else is at fault here. Anyone can chime in to add info that would be great.
Cfg version, if the data layout changes ever, Ignore for now.
CFG:01.01
# Compatible SMBIOS versions, Ignore for now.
VER:02.03
VER:02.06
# Manufacturer
01,04,S,"ALCATEL"
# Family
01,1A,S,"8996"
# Product Name
01,05,S,"IDOL4S"
# Version
01,06,S,"1.0"
# Blank line needed after the last config