I have tested it before and now also.
gbak -c -v -START 123456789
and database after restore looks like
Database header page information:
Flags 0
Checksum 12345
Write timestamp Aug 9, 2019 15:17:08
Page size 4096
ODS version 16.0
Oldest transaction 123456790
Oldest active 123456791
Oldest snapshot 123456791
Next transaction 123456850
Sequence number 0
Next attachment ID 0
Implementation ID 16
Shadow count 0
Page buffers 2048
Next header page 0
Database dialect 3
Creation date Aug 9, 2019 15:17:07
Backup timestamp Aug 9, 2019 15:17:08
Attributes force write
Variable header data:
Sweep interval: 20000
*END*
regards,
Karol Bieniaszewski
Firebird-Devel mailing list, web interface at
https://lists.sourceforge.net/lists/listinfo/firebird-devel