Might peek in the Configuration ... Product Listing ...
Display Product Listing Default Sort Order
Product Listing Default sort order?
NOTE: Leave Blank for Product Sort Order. Sort the Product Listing in the order you wish for the default display to start in to get the sort order setting. Example: 2a
This will provide the listing by the physical sort order you enter for the products ...

This allows you to be specific about the order of your products ...

While you could use the products_id by altering code, you will find later entering a new product would throw it out of order ...

If your current order is correct, you could update the products_sort_order by the products_id * 10 which would then set the value to 10 x the products_id ... this allows you to later add new products and enter them between old products ...