Section 16 (2) (aa) reads as follows: the details of the invoice or debit note referred to in clause (a) has been furnished by the supplier in the statement of outward supplies and such details have been communicated to the recipient of such invoice or debit note in the manner specified under section 37;
Section 37 (1) reads as follows: Every registered person, other than an Input Service Distributor, a non-resident taxable person and a person paying tax under the provisions of section 10 or section 51 or section 52, shall furnish, electronically, 2[subject to such conditions and restrictions and] in such form and manner as may be prescribed, the details of outward supplies of goods or services or both effected during a tax period on or before the tenth day of the month succeeding the said tax period and such details 3[shall, subject to such conditions and restrictions, within such time and in such manner as may be prescribed, be communicated to the recipient of the said supplies]:
It is obvious that subject Bill of entry (i.e. manual or otherwise) will not be reported by anyone in Form GSTR-1u/s 37 (1).
Furthermore, Bill of Entry (i.e. manual or otherwise) is NOT the invoice u/s 31 but falls under 'such other tax paying documents as may be prescribed' as per Section 16 (2) (a) read with Rule 36 (1) (d) for availing ITC (i.e. a bill of entry or any similar document prescribed under the Customs Act, 1962 or rules made thereunder for the assessment of integrated tax on imports;)
Summarising above, any Bill of Entry (i.e. manual or otherwise) need not be reflected in Form GSTR-2B for taking ITC because the conditions prescribed u/s 16 (2) (aa) read with Rule 36 (4) does not apply to Bill of Entry.
These are ex facie views of mine and the same should not be construed as professional advice / suggestion.