SQL Developer 4.1.0.19 64-bit
When using sqlformat insert, SQL Developer (and sqlcl) will put quotes around the target table name if it's no upper-cased e.g.
set sqlformat insert
select * from dual;
returns
REM INSERTING into dual
SET DEFINE OFF;
Insert into "dual" (DUMMY) values ('X');
which is incorrect since the quotes then make the table-name case-sensitive (yes, I know I can't actually insert into DUAL) and won't match the actual table.
IMHO it would be better to only use the quotes if the original request included them, since otherwise the source table is case-insensitive.