The .38 Super Cartridge is a .38 ACP +P Round. You can shoot .38 Super +P in that gun as the +P was added to distinguish it from regular .38 ACP cartridges.
Yes you can also use .38 ACP ammo in the gun Specified.
It is equivalent to shooting .223 instead of 5.56. Or .38 special instead of .357 magnum.
Or .44 special instead of .44 magnum.
Have fun out there.

Vincent - Better red your owner's manual. I would imagine it tells you that using any ammo other than that for which the gun was designed would void your warranty. Do what the owner's manual says. there are good reasons the manual was written the way it is.

"When I asked the Rock Island representative at the trade show if the M206 is rated for +P ammunition, he said I could go ahead and shoot it. Readers have reported that when they contact Rock Island they get the same answer. However, if you look at the M206 barrel markings, the owner's manual, and the company website, the gun is referred to as being a “.38 Spl.” with no mention of +P ammunition. On page 5 of the owner's manual it reads, "The M200 REVOLVER is chambered for Cal. .38 Special cartridges manufactured in accordance with standard industry practice." It could be argued that this statement includes SAMMI specification +P loads, but it's not very specific. " americanrifleman.org/articles/2015/7/23/rock-island-armory-m206-38-special-revolver-review/

Vincent, for safety and warranty reasons you should get the manufacturers recommendation, Rock Island Armory/Armscor at Phone: (775) 537-1444.