By alloy steel, Ruger refers to Chrome Molybdenum alloy steel meaning blued steel as opposed to Alum alloy or stainless steel. Your Buckeye is all Chromoly including grip frame and ER housing. So is the 38-40; most special models are and all Super BHs of recent manufacture (earlier ones had alum ERHs). See below for complete application details of all models.
Which Blue Models use Alloy Steel or Alum Alloy GFs and/or ERHs:
Blue steel GFs* on the following:
All New Model Blackhawk flat top and New Vaquero mid-size main frames, XR3 size (also cut for indexing pawl system, no extensions into main frame & only 7/16” thick).
All Super BHs: XR3-RED size on short brl. lengths; dragoon size on 7 1/2" & 10" barrels.
All original full-size Vaqueros & .32 Mag Vaq. style single sixes had the XR3-RED size SHORT GFs (500 .32 Mag Vaqs had the XR3-RED size.
All Bisleys.
Old Army beginning 1985.
Aluminum alloy grip frames on the following:
All blue single sixes 22 and 32 (except the 32 Mag Vaq. style and Bisley 22s & 32s).
All full size main frame Blackhawks XR3-RED size (not including Bisley Blackhawks).
All Old Models, XR3-RED GF, pre 1973 (except Super BH).
All Old Models, XR3 GF, pre 1963.
Old Army pre 1985.
Steel ERH*:
All New Model Blackhawk flat top and New Vaquero mid-size main frames.
All Super BHs in all barrel lengths (including 5” ERH on 44 & 357 Max 10” barrel) from the recent past c. 10 years.
All original full-size main frame Vaqueros.
All old models including Bearcats prior to c. 1962.
Alloy ERH*:
Guns with alloy grip frames usually have alloy ejector rod housings except early old models which had steel until c. 1962.
Also, except for recent years, NM Super BHs and early original full size Vaqueros had alloy ERHs.
Stainless and blue Bearcats have alloy ERHs and old model Bearcats which had steel until c. 1962.
*NOTE: There are a several dealer exclusive model exceptions to the above like the Buckeye convertibles, etc.