Hi ez 210,
Welcome to the IFSQN forums.
If you were manufacturing a product for me I would expect it to be included in your HACCP (Food Safety) plans.
Your clients should send you sufficient information about the raw material/packaging/ingredients they supply in order for your team to assess if there are additional hazards associated with those.
SQF requirements are in Section 2.4.3 Food Safety Plan (Mandatory).
Clause 220.127.116.11 A food safety plan shall be prepared in accordance with the twelve steps identified in the Codex Alimentarius Commission HACCP guidelines. The food safety plan shall be effectively implemented and maintained and shall outline how the site controls and assures food safety of the products or product groups included in the scope of the SQF certification and their associated processes.
So, answering your question you need a HACCP plan to cover the scope of the products/product groups. Your products and your client products could be regarded as one product group if they are similar and undergo the same processes.
I doubt the SQF would let you exclude your Clients products from your scope of certification, even if they did allow that exclusion, if I were your Client I would be very unhappy that my products were excluded from a site food safety certification.
It doesn't appear to be too much trouble to include both you own and your clients products in your HACCP (Food Safety) plans so that is what I would do and this also means a bit of peace of mind.