Good question, and I don’t know the answer. Remington has shown a LOT of variation in their headstamps over the years and I have never heard a reason for the variation. This is unlike Olin/Winchester who remained very consistant with their W-W and then WIN headstamps. In the past 5 years or so Olin has also contracted out some of their case manufacture, notably to S&B in some calibers, but not 9x19mm that I know of.
Over the past few years, I’ve been told that some of the variation was due to Remington contracting out their headstamp bunter manufacture (or perhaps the hob used to make the bunter) and the result was slight variations in many of the headstamps.
The only case where Remington has contracted out their case manufacture that I know if is when they moved manufacturing to Arkansas. In this case, they contracted with Olin for cases in a number of calibers including 9x19mm. These cases were identified with a small diamond between the R and P (R<>P). In 9mm, I don’t believed any of these cases were loaded by Remington. Most of the ones I have seen were loaded by 3-D on ammo sold in Europe.
By the way, the headstamp you asked about appears to have been introduced in the late 1980s and used into the mid 1990s, but that is just based on when I found my specimens for sale as new commercial ammunition.
This is a really long post when all it really says is “I don’t know”. Sorry!