The SL-88 was Filli. Gamba's design. It's a true BOSS boxlock with a removable trigger, not unlike Perazzis design, but never proved as popular. Well built guns, the SL-88's design was sold to Filli's cousin Renato, at which point it became known as the Daytona. Interestingly, Filli. Gamba was actually building prototype SL-88s for Remington, when the deal fell through he sold the design. The prototype Remington-marked SL-88s are still in Italy.
I've never seen an SL-88 for sale, but early Daytonas seem to languish with $2,500-$3,000 price tags... and they have better triggers. SL-88s are known for breaking springs, and unlike a Perazzi, replacements are falling from the heavens in vast quantities. For many, it's just another gun that, regardless of how nice it is, isn't a Beretta or a Perazzi.
Obviously, pictures would help!