Parallel INSERT

This seems a good starting point:

--TESTING
DECLARE 
    @request_info varchar(1500),
    @request_user_id int;
        
SET @request_user_id=21;
SET @request_info='info3';
--/TESTING

--QUERY
DECLARE  
        @record_id int,
        @userid int;

BEGIN TRANSACTION
SELECT @record_id=id,@userid=userid FROM test WITH (UPDLOCK,HOLDLOCK) WHERE info=@request_info

IF @record_id IS NULL
BEGIN
        INSERT INTO test WITH (TABLOCK) (info,userid) VALUES (@request_info,@request_user_id);
        SELECT SCOPE_IDENTITY()
END
ELSE IF @userid!=@request_user_id SELECT NULL
ELSE SELECT @record_id
COMMIT
--/QUERY

it worked in all my tests.

Do you have suggestions/comments about this last query?