Could however also be a 1990 frame too....
The 90 and 91 non e-stay frames had similar features like the internal brake cable routing, the non pierced seat tube/top tube and the double eyelet drop-outs on the lower end frames.
What is different is the square section seatstay bridge. My 91 Sahara has a round bridge, while my late 91/early 92 e-stay Kili Racer has a square section bridge.
I suspect then that Saracen were using the square section bridge on frames produced in 1991 and perhaps 1992. They may have been using them in 1990 to but I can't find any photos showing this.
So, still sticking with a 1991 frame, it could well be higher up the range than a Sahara. Could be Tufftrax, Andes or Traverse Hydrotech.
According to the 91 catalogue, the Sahara had 17" chainstays, while the other three mentioned had 16.75" stays. So measuring those could rule out a Sahara. If the Magura sticker is a clue then perhaps it's a Traverse Hydrotech... Who knows?
I've also found an image of a 1992 model year Sahara Elite which, wouldn't you know it, has a square section bridge along with all the other features of your frame.
But the lower end Saracens often seem to have used 'leftover'
framesets from the previous model year. 1990 frames used in 1991 for example. They also got rid of surplus frames and components by building up non catalogue 'Special Edition', 'Race' and 'Elite' bikes.
Because of this, exact dates for Saracens are notoriously difficult to pin down once the decals and original components have been removed.
The serial numbers seem pretty meaningless and random too.
So then, I'm still sticking with your frame being produced in 1991, but I'm not entirely convinced it's a Sahara.