This HL2 is clearly labelled as to type on the base. The base also carries the impedance of 16,000Ω the μ of 24 and the mutual conductance of what is 1.5 or 1.3 it is not clear. What it does not have is a makers name.
The base style matches that used by Brivaron and 362 Radio Company.
The Text imprinted into the base.
The base: the impedance rating is the only clear lettering.
The balloon envelope is 45 mm in diameter, and excluding the B4 base pins is 97 mm tall.
References: Inspection, datasheet & 1043. Type HL2 was first introduced in 1931.