After increasing my K series lens collection over the past couple years, I found information relating to the original lens hoods greatly lacking. Even top notch sites like "Bojidar Dimitrov’s Pentax K-Mount Page" are confusing with their lens hood terms.
Even though there are a couple of exceptions, you can generalize that K series lens hoods are plastic clip-on and come in two filter thread sizes, 52mm & 58mm. The terms PH-S58 did not exist back then and lens hoods were marked with the filter thread size on the back and the lenses the hood was designed for on the front. Rubber, mental and screw mount hoods were generally not used for the K series lens hoods. The clip-on lens hoods for wide angle and standard lenses came with a hard case, the clip-on telephoto hoods were designed to fit in the hard lens case with the lens.
The following is a list of all K series lenses and indicates if they have a clip-on or built in hood. I have made up my own name for each hood and have attached pictures of the front and back if possible.
K15/3.5: Built-in hood
K17/4 Fish-eye: Built-in hood
K18/3.5:
Square 58mm - Ultrawide
K20/4:
Square 58mm - Ultrawide
K24/2.8: Dedicated square 52mm plastic
K24/3.5:
Square 58mm - Ultrawide
K28/2:
Square 52mm - Wide
K28/3.5:
Square 52mm - Wide
K28/3.5 Shift: Built-in hood
K30/2.8:
Square 52mm - Wide
K35/2:
Square 52mm - Wide
K35/3.5:
Square 52mm - Wide
K50/1.2:
Square & Round 52mm - Standard
K50/1.4:
Square & Round 52mm - Standard
K50/4 Macro: Not required
K55/1.8:
Square & Round 52mm - Standard
K55/2:
Square & Round 52mm - Standard
K85/1.8:
Round 52mm – Short Telephoto
K85/2.2 Soft: Round 49mm – Short Telephoto
K100/4 Bellows:
Round 52mm – Short Telephoto
K100/4 Macro:
Round 52mm – Short Telephoto
K105/2.8:
Round 52mm – Short Telephoto
K120/2.8:
Round 52mm – Telephoto
K135/2.5:
Round 58mm – Telephoto
K135/3.5:
Round 52mm – Telephoto
K150/4:
Round 52mm – Telephoto
K200/2.5: Built-on hood which extends
K200/4:
Round 58mm – Telephoto
K300/4: Built-on hood which extends
K400/5.6: Built-on hood which extends
K500/4.5: Built-on hood which extends
K1000/8: Built-on hood which extends
K1000/11 Reflex: Built-on hood which extends
K2000/13.5 Reflex: Built-on hood which extends
K28-50/3.5-4.5 Zoom: Dedicated round 52mm screw-on metal
K45-125/4 Zoom: Dedicated round 58mm - 67mm screw-on two part metal
K80-200/4.5 Zoom: Built-on hood which extends
K85-210/3.5 Zoom: Dedicated round 67mm screw-on metal
K85-210/4.5 Zoom:
Round 58mm – Telephoto
K135-600/6.7 Zoom: Built-on hood which extends
K400-600/8-12 Reflex Zoom: Dedicated round 67mm screw-on metal
Square 58mm - Ultrawide Dedicated square 52mm plastic for the K24/2.8 Square 52mm - Wide Square & Round 52mm - Standard Round 52mm – Short Telephoto Round 49mm – Short Telephoto Round 52mm – Telephoto Round 58mm – Telephoto Dedicated round 52mm metal for the K28-50/3.5-4.5 Dedicated round 67mm two part metal for the K45-125/4.0 (The thin part on the right is a 58mm - 67mm step-up ring) Dedicated round 67mm metal for the K85-210/3.5