In my opinion, it's a rare gun in this configuration. I know of only 5 total Model 27 Marked Nickel finished 6-1/2" barreled guns including the ones mentioned in this thread and mine. My gun S/N S188681 shipped 6/25/63 to Gil Hebard Guns.
Sorry, but those values are based on standard Model 27 valuations listed in the book. A standard Model 27 (no-dash) ANIB was listed at $900, so 2X is around $2000 value. Model 27-1 states value is $3500. The Model 27 (no dash) was manufactured from 1957 to 1960. The Model 27-1 was only made one year, 1960. The difference between Model 27 and 27-1 was stated as a change in the extractor rod, right hand to left hand thread. Nothing here is set in stone, but interesting assessment of early Model 27 revolvers values.
As we all know, manufacture dates and ship dates vary. My 27-1 with 6" barrel shipped 08/1962.
T4's gun may not qualify as "rare", but many of us would be proud to own it.
I'll tell you what!! If I'd have known Gil and Mary Elizabeth Hebard had a store in Knoxville, Tennessee, I'd have been camped out there pretty much full time---just wasn't paying attention I guess.