Yes, you can order the engine without senders and panel but you will not save any money.
Remember that these items must be fitted for the engine to be tested at the factory and then there is extra labor to remove everything. before the engine is painted and packed.
The oil sender is 1/8" BSP thread.
The temp sender will be either 1/8" BSP or 3/8" BSP depending on the equipment spec of the engine.

To fit my Beta 35 I had to modify many of the fluid connections and found getting BSP fitting and sensors difficult to find in USA or very expensive. I found that Amazon had many adapters available in BSP to NPT. They all were well made brass or 316 stainless steel and all came out of Hong Kong - I guess the old British standards are still there. It took a week or two to get them. I used the almost new VDO 1/8"NPT oil sensor(which was a dual terminal with analog and on/off signals) off my Volvo MD11D with an adapter for the Beta 35 so as to retain my VDO oil pressure gauge which was installed in my Navg station.

When you look at all the components on the back of the BW gauge to make the pushbutton you might want to consider using a BW  or similar smaller

gauge in your new panel plus add the extra VDO gauges you want. The water temp gauge/ overheat light is rather unique in that the senior only produces the analog signal and the temperature gauge derives the on/off signal for the overtime light. The same is true for their oil pressure gauge. Beta has detail wiring schematics of how all this works so you need to study them carefully as the gauge and pushbutton controls are quite unique and fairly complex and not what you would expect.

 

These are parallel threads