In ConfigureShard(), sv_offerEnable lists offerIds from offers.xml (same folder, look for the offerId attribute). Numbers separated by comma, space or tab; empty string disables all offers.

-- List of offerId offers to enable on the shard server.
cvars.sv_offerEnable = "6,7,17,18,19"
Find the offerId you want in offers.xml, add or remove its number here, restart the shard.
Additional Notes: 

IDs come from offers.xml in the same folder.

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