It's not called a Sendero SF1, it's just simply called the "Sendero SF". The newest model is actually designated by Remington as the "Sendero SF II".
The original Senderos were blued rifles, and non-fluted heavy barrels.
Here's how the generations go, and how they are distinguishable:
Sendero - Blued rifle, jeweled bolt, non-fluted heavy barrel, black & gray HS Precision stock, no palmswell, single swivel stud.
Sendero SF - Stainless rifle, jeweled bolt, stainless & fluted (SF) heavy barrel, same black & gray HS Precision stock as the original Sendero.
Sendero SF II - Stainless rifle, jeweled bolt, stainless & fluted heavy barrel with black painted flutes. A new style black & gray HS Precision stock that has a heavy palmswell and double swivel studs and a flatter wider forend.
Your rifle is a Sendero SF. It's not some dealer-only special run deal. I have the exact same rifle, bought it brand new 12 years ago from the outdoors store I was working at, and it doesn't say the word "Sendero" on it anywhere, except the box it came in.
To my knowledge, the STW's and the RUM's were pretty much the only calibers that were never stamped with the word "SENDERO" on the barrel after the caliber designation.
Here's a picture of the caliber on the barrel of my Sendero SF 7mm STW.