Yes. You still need to send upload the accepted manuscript on Symplectic Elements as soon as possible (and certainly within 3 months of acceptance) as you will still need to comply with the REF Open Access policy.
If you have co-authors whose funders have an Open Access policy, that will also apply to the paper and you will need to comply, even if you didn’t receive the funding yourself. This is also irrespective of the part your co-authors took in the work. In this case, you should follow the normal procedure and upload the accepted manuscript to us via Symplectic Elements as soon as possible, taking care to indicate any source of funding acknowledged in the paper, and then wait for our response about whether or not you would be eligible for payment of Gold Open Access through our block grants.