Dear Steve
I am not sure which book you extracted this important information. I am assuming this is the production for Seville from the title of the book.

Bocas de Fuego y gualderas para morteros construidadas desde 1773 a 1795:

Guns and mortars constructed 1772-1775
[Cañones] de a 4 cortos..................................524.....Gribeauval 4-pdrs
[Cañones] de a 4 recámara cónica...................36.....Maturana 8-pdr Unicorn
...
[Obuses] de a 4 ..............................................232....4-pdr Mountain Howitzers
[Obuses] de a 3 ............................................. 170....3-pdr Mountain Howitzers
...."

A full list and reference would be greatly appreciated. Again thank you. Date of commencement of production of the pieces would be helpful. Another piece to throw out the premise that Gribeauval System was introduced in 1783 that is repeated universally in English sources.

Stephen