From Wellington's Dispatches Volume 6, page 143:

Memorandum from Wellington to Brigadier General Cox about Fort Concepcion, dated 27 May 1810

Four Portuguese 6 pounders ready to go from Almeida immediately.
Four Spanish 8 pounders, Eight Spanish 4 pounders: carriages to be prepared immediately
Two Howitzers, ready to go from Almeida immediately
All to have 100 rounds per gun.

It is not much but there was some guns there.