I don't believe any of the Notes have the new LTE band for rural areas. The first phone to have those is the LG V30.
You're thinking of lte band 71 600 mhz. T-Mobile did say the LG V30 was the first phone to have that band but I haven't seen a single site list it in the specs so not sure if it has it or not.
Notice the band differences between the S8 TMO version and Unlocked version:
S8 G950T (T-Mobile)
LTE band 1(2100), 2(1900), 3(1800), 4(1700/2100), 5(850), 7(2600), 8(900), 12(700), 13(700), 18(800), 19(800), 20(800), 25(1900), 26(850), 38(2600), 39(1900), 40(2300), 41(2500), 66(1700/2100)
S8 G950U (Unlocked US)
LTE band 1(2100), 2(1900), 3(1800), 4(1700/2100), 5(850), 7(2600), 8(900), 12(700), 13(700), 17(700), 18(800), 19(800), 20(800), 25(1900), 26(850), 28(700), 29(700), 30(2300), 38(2600), 39(1900), 40(2300), 41(2500)
Can anyone confirm if changing the sim or firmware really changes the lte bands?