No TRS-80 used hard sector disks. (Speaking here as a former owner of examples of both the Model I/III/IV and Color Computer lines. Single hole soft-sector *only*.) Note that some Apple/Commodore-type people, whose computers don't use the index hole at all and could work with either kind of media, confuse systems which use the (single) index hole in a "soft-sector" diskette as being "hard sectored". A true hard-sector disk has numerous holes spaced around the disk medium marking every physical sector boundary. Soft-sector systems just use the single hole to synchronize the "starting line" for each track.
Honestly I've only seen hard sector disks in the wild twice. Once was on a Heathkit H89, the other was on a *very early* dedicated word-processor/typewriter thing called "QYX", made by Exxon's long-dead office products division. (I actually owned the latter, saved from a garbage can. About the only reference to it I can find on the Internet is a passing mention in a Popular Mechanics article about the history of typewriters.) Hardly anything beyond the Altair/IMSAI/S-100 era used them. (And in many cases the old systems using them were upgraded with newer controllers to eliminate the need for them later in their lives.)
It's practically impossible to buy hard-sectored diskettes anymore, so really it's sort of a theoretical argument. If you have a system that needs them you'd better have already stocked up around 1983 or so. (Well, okay, I found a joint selling them for $14 each. OMG!)
EDIT: A mailing list post detailing a HOWTO for making your own hard-sectored disks out of soft-sector blanks. Reading it should make the difference more clear.