We use 360 as north and yes, we can use 3 digits so your example would be 360150kt. The only times I can recall seeing three digits is in reports as hurricanes came ashore. From the Federal Meteorology Handbook which is the guide for weather observers:
The wind direction, ddd, shall be coded in tens of degrees using three figures. Directions less than 100 degrees shall be preceded with a "0". For example, a wind direction of 90° is coded as "090". The wind speed, ff(f), shall be coded in two or three digits immediately following the wind direction. The wind speed shall be coded, in whole knots, using the units and tens digits and, if required, the hundreds digit. Speeds of less than 10 knots shall be coded using a leading zero. The wind group shall always end with KT to indicate that wind speeds are reported in knots. For example, a wind speed of 8 knots shall be coded "08KT"; a wind speed of 112 knots shall be coded "112KT".