MP15T LOWERS

[roman rapido]

I just noticed that there are 2 types of S&W M&P 15T lowers out there. One shows the SW xxxx (Serial No.) and the words Model MP15 and Cal. 5.56 mm below it.
The other one shows SM (Serial No.) and only the word Model MP15.
Are these 2 the same make ?

Is the second one for civilians only ?

I appreciate any info.

Thanks

[roman rapido]

The M&P 15 T lower that has the serial numbers starting with the letters SW and with the labels Model MP15 and Cal. 5.56 mm is only for the caliber 5.56 upper only,,,,The other lower with the letters SM can be interchanged for 5.56mm, .223 and other caliber uppers.
Sweet. Way to go Smith & Wesson.