Undocumented lateral transfer front site to IBM

After doing some research with other members, it appears that this Brazed front site was made by subcontractor named Prestol and was marked with a PD over SG and it appears to be a formally not reported and undocumented lateral transfer part that may have went to IBM early 1944. Dan Pinto did an amazing article 4 years ago it said the following;

Does anyone else have a front site made with these manufacturer stamps?

War Baby1 pg 429 shows Prestol Div of Detroit Harvester as being an added subcontractor for Saginaw Grand Rapids plant. It shows no part marking

War Baby 3 add the marking just as "PD" however states it was Planert Skate as the manufacturer.

War Baby 1 page 405 shows  Planert Skate Company as being added to make front sights for Rockola and marked RP

Has anyone ever observed a type 2 sight marked just PD?

I believe this was an error fitting a code to a known manufacturer. Think about it, what would PD mean? D is not a code for any prime contractor.

The simple answer is PD stands for Prestol Devices, and the SG below clarifies that it was for Saginaw Steering Gear.

War Baby 1 pg 114 has the information of the introduction to the fabricated (stamped/brazed) components and in Jan 1943 fabricated sights made by Prestol were being experimented with.

Sights were sent to Inland and Underwood.

We know that Prestol made front sights, as well as Simpro. There is no indication that Planert, who only made front sights mentioned above, made any fabricated front sights.

I discuss the fabricated front sights as well as the markings here

Here we have some transfer Type 2 front sights. We know Prestol made the front sights marked P as well as PO B, PO Q, EU, PD/SG. What is not addressed are the Tyoe 2 front sights marked RP as shown below. If you compare the font to the RP marked on the front you will see they are not consistent. With the transfers of known markings used by Prestol, and absent any other info I would say that Rockola needed some front sights and Prestol had some of the sights marked for other prime contractors on hand and over stamped them RP.

It is possible they were transfers from other prime contractors as we know Underwood sent RO front sights. QHMC was right down the street and we have seen some undocumented transfers between them.

As to the Prestol PD/SG marked front sight on on an otherwise original looking IBM with no sights of the front sight being off, I would say that it is probable that they were sent directly from Prestol to IBM, possibly in with the PO B sights.