From this photo of the Sahand 74 under repair and conversion, it seems clear that there is no more room at the bow for the Sayyad-3 SAMs.
View attachment 116932
There should still be some free space at the stern of the ship, but at that point with the 30mm CIWS + its superstructure + the superstructure containing the optronic targeting + 4 canisters for anti-ship missiles, the weight becomes excessive.
Alternatively, they replace the Sayyad-3 SAMs with smaller vertical launch missiles (VLS), I wonder if what I circled in red is actually a modification to install the VLS.
View attachment 116933