hello, i live at indonesia, my friend recently bought a motorcycle from united states, he bought harley davidson duo glide 1958 but the front shell case headlamp stainless stell which on front head lamp has "HYDRA GLIDE" sign, not "DUO GLIDE" sign, according to the seller it is the transformation from hydra glide to duo glide, it is the first duo glide era which has HYDRA GLIDE shell case head lamp stainless stell, my friend dont know where to asked this question, he asked me to look for this answer, i am looking for your help. Is it should be DUO GLIDE OR HYDRA GLIDE which on the shell case stainless steel on the front head lamp, i attach you the pictures, and also if you dont mind, please email me at anggorohart at gmail dot com for the answer, thank you so much and GOD BLESS AMERICA

 

Duo-Glide refers to the fact that the bike had spring action front (as in hydraulic forks and rear (as in shocks as opposed to rigid). Your 58 should be in a swingarm frame (58 was the first year of the non-rigid pans).

The Hydra-Glide just refers to the front end. From your pics it appears you have the correct tin for 58

 

The first Hydroglide was made in 1948. I have one because I was born that year. Not much as changed in reality since then to the current new models. Little changes only.

Rear is a HardTail not shocks: This is a 1950

 

Actually 48 would have been a springer front end. The front end on the bike in the pic would have been introduced in 1949. Springer front end was still an option for 1949 however.

49 had some odd-ball stuff like sliders that were cast with a part number, early one had a front brake backing plate with a 48 part number (sand cast) and then there is the damper assembly atop the tubes that evolved over the course of 1949 as well. Been working on getting my 49 EL correct for the last 7+ years.