What would make you think it's NOT required? I would say the answer is an unequivocal yes. Here's what they said in the federal register on UDIs:
There were a number of comments regarding the applicability of the UDI requirements of § 801.20 to combination products with a device constituent part, convenience kits, in vitro diagnostic products, and HCT/Ps regulated as devices.
These products are devices, contain devices, or are regulated as devices, and are therefore subject to the requirements of this rule.
I think they're not requiring still for Class I exempt devices but I think even that deadline is approaching soon.
That's less clear. It's been my experience that submissions are made with placeholders for UDIs. As long as you're set up prior to distribution, I think you're fine. It's not an instant thing and, depending on your product configuration, can get tricky, so I wouldn't wait too long.