There is no requirement to be Ranger Tabbed prior to SFQC, however some Group Commanders have made it a pre-requisite for those folks to go before they take over an A-Team. COL Potter, circa 1981, when he was the commander of 10th Group tried to send all his CPTS and LTS to Ranger School. While it is not a requirement, it is good training and a Ranger Tabbed officer has one big advantage over an SF officer who is not-that Ranger Tab keeps him just a little bit dryer under the tab than one without the Ranger Tab.
I will also take this one step further. When I was but a wee lad in the Infantry Officer Basic Course I received orders for my first assignment in Germany. The opening paragraph read, "Welcome to the Ranger Battalion". That prompted me to go to Ranger School. When I arrived in Germany I found out that the Ranger Battalion took its name and heritage from the 36th Infantry out of Texas and coined the Ranger Bn name in honor of the Texas Rangers and had absolutely nothing to do with the Ranger mentality at all as it was a mechanized infantry battalion in the 3rd Armored division. Talk about a fish out of water, I was one of a handful of infantry officers in the battalion with airborne and ranger schools under his belt. If you don't think that is a dangerous combination, just ask any of the QPs on this forum about 2LTS who think that they know their way around the woods because they sported a set of jump wings and a Ranger Tab. I believe I hear a "Sweet Baby Jesus" erupting from somewhere south of Panama.
Jack Moroney