Please to help with this South African pattern pieces coins

Hello
I have this is 3 pattern pieces South Africa coins 1989 year
letters: B C D
Can to help with mintage and market value?
Thank a lot

Hello parmalat, those are very interesting and I had never seen anything like them but I have found them in my 2012 edition of Hern's Handbook on South African Coins & Patterns. It seems they were struck by the South African Mint when the currency issues changed to the new clad coins and Hern's text describes them thus:

"T30 to T38. With the change over to the new clad coins, the mint issued pattern pieces to the public in a white envelope and later in a brown envelope (but a set of loose pieces and a set in a special white envelope was also made these were not issued to the public). All, issued to the public, had the Mint protea on the obverse with a Letter A=R5, B=R2, C=R1, D=50c, E=20c, F=10c, G=5c, H=2c & J=1c. These were used by manufacturers of vending machines to calibrate their equipment. These pieces could be returned to the Mint for a full monetary refund."

With regard to the mintage and value, my 2012 edition has the following data:

TA 38 Set 1a
Date 1989
Mintage under 30
Unc R35,000

TA 38 White Set
Date 1989
Mintage 500
Unc R250

TA 38 Brown Set
Date 1989
Mintage 30 000
Unc R50

I have reproduced the information as faithfully as possible and hope this is of some help

thank you very much