Can someone let me know the pearlescent that comes on the stock Gasoline Green, Harbor Blue, Sunrise Orange, Olive Green and Cabernet Red LSC metallic paints? Or is there a lookup guide somewhere?
There are 13 metallic paints with a non-LSC pearlescent:
Metallic Torino Red has Worn Shadow Silver pearlescent
Metallic Lava Red has Matte Yellow pearlescent
Metallic Garnet Red has Worn Blue Silver pearlescent
Metallic Sunset Red has Worn Golden Red pearlescent
Metallic Cabernet Red has Worn Golden Red pearlescent
Metallic Candy Red has Worn Blue Silver pearlescent
Metallic Sunrise Orange has Worn Shadow Silver pearlescent
Metallic Olive Green has Worn Green pearlescent
Metallic Bright Green has Worn Green pearlescent
Metallic Gasoline Green has Worn Sea Wash pearlescent
Metallic Saxon Blue has Worn Baby Blue pearlescent
Metallic Mariner Blue has Worn Baby Blue pearlescent
Metallic Harbor Blue has Worn Sea Wash pearlescent
Additionally, pure and brushed gold metal come with a non-LSC yellow pearlescent.
You can keep the pearlescents from any of the metallic/metal colors on a crew color by first applying the metallic/metal color then applying your crew color.
Finally, to answer OP's question, paints in GTA are defined to have 3 distinct components:
(1) "texture", or how reflective/absorptive the paint is
(2) "color", or the RGB hue of the paint,
(3) "pearlescent", an additional hue that reflects light in a different way, and may also have a texture name attached to it.
So let's build colors based on the naming scheme of "(1) (2) with a (3) pearlescent": You can think of "texture" as roughly the big categories of paint you can choose from at LSC: Classic, Matte, Metals, Chrome, etc. Each of those textures then can be a different color, e.g. Black, Silver, Red, Green. Further, you can then add another texture/color pair as pearlescent, like White, or Matte Yellow.
So, for example, complete paint descriptions are something like:
Matte Olive Drab with an Ice White Pearlescent
Worn Dark Red with a Worn Dark Red Pearlescent
Classic Black with a Black Pearlescent
Notably, in the pearlescent component, the texture clarification is often omitted when it's a Classic color, so "Ice White Pearlescent" is "(Classic) Ice White Pearlescent". Furthermore, "Black Pearlescent" appears in-game as if there is no pearlescent. Rockstar has pre-ordained particular texture/color/pearlescent combinations as ones available in LSC, and furthermore has some that are not in LSC.
The Worn category is then a (1) texture type, which is totally unobtainable in LSC! No worn color is available in LSC because the entire category is missing from the Respray Menu, even though certain vehicles spawn in-game with worn textures. So, it is possible to obtain legitimately a Worn paint vehicle, but you must find it and steal it in-game. This is not the same thing as "Rust" or "Wear" on vehicles, which is a separate effect applied to certain vehicles.
Finally, note that modders can make ANY texture be ANY color with ANY pearlescent. So, their combinations are not limited to the specific combinations of texture/color/pearlescent that Rockstar implemented. Through Crew Colors, Rockstar has allowed normal players to change the color of, and add a pearlescent to, only the Utility texture in LSC.