GST will have to be paid on inputs and input services received by such manufacturer under reverse charge at normal rates and not at the composition rates. Purchase from a person under the composition scheme is purchase from a registered person and hence will not attract tax under reverse charge under section 9(4) of the CGST Act, 2017. Any person migrating from the existing law to a composition scheme and holding stock of goods purchased from unregistered persons is required to pay tax on such goods.
(FAQ 40: MSME)