The Dayton guns weren't the only 4" HB Model 14s made. I have a Model 14-3 in that configuration serial # 1K74XXX. Factory letter says this gun was shipped July 15, 1971 to Dave's House of Guns, Dallas, TX. Letter also confirms that this gun did leave the factory with a 4" barrel.
Indications are that this was part of approximately 100 guns shipped to three big wholesale distributors in July, 1971. Olympic Wholesale, Los Angeles, Daves House of Guns, Dallas and Gil Hebbard, IL. Its thought the they were a market test for this configuration. So this later gun is actually rarer than the Daytons.
Anybody care to take a guess what mine may be worth? No box or papers. It ain't for sale, but I am curious.