Assembly line Weatherhead petcock radiator drain
 

Very nice original assembly line installed Weatherhead petcock with original Weatherhead logos on the underside and 94 stamp. Originals are very hard to find. $60 ppff

Rich from my experience with 1970 Chevelle Big blocks (can't speak for other models)
The assembly line Petcocks I have seen have also had the Weatherhead or Eaton Logo right on one side of the bolt and the bottom had a unique flat head notch.
See photos.

What you have IMO is an over the counter unit if it does not have a logo on one bolt side.

Danny, thanks as always good info :-)
Here's some of the observations of some of the other original petcocks I have and the different configurations they came in.
1 brass tube no logo on underside of arms. Weatherhead stamped on flat,

2 steel tube no logo on underside of arms. Weatherhead logo on flat

3 no tube 94 + <w> stamped on arms (which is installed flats away from radiator

4 steel tube 94 <w> stamped on arms. Weatherhead stamped on flat

I have also seen 1, 2 and 4 on late 60's early 70's.

Here's a picture of some original of what I believe are assembly line eaton petcocks. They don't have stamping on the brass but they have the ridge on the underside of the arms. Most hexes have a line a vertical line or two running up and down from the stamping process.

Two more original Weatherhead petcocks. One with brass tube one with steel tube. $60 each ppff

Assembly Line Eaton Petcocks both from a 1970 Chevelle SS Big block,
Like I mentioned below that I can only reflect on 1970 Chevelle's don't know or study any other models.

New prices $45 each

$35 each