Availability of Off-table Artillery during Recon Phase

Hello togehter,
I have a question regarding the availability of off-table artillery during the recon phase when only units with the "Scout" special rule can be deployed.

When I bought an off-table artillery or mortar battery is this artillery already available in the recon phase together with the scout units or can they only deployed when the main forces arrive? This would be an advantage compared to on-table artillery of course.

Thanks for help and clarification!

yes, it is availablefrom the start of the game