Yes, it is Gao Style. Yang style would never be effective in combat alone unlike Bu Di Zhen which is more similar to Chen style.
The Wudang monks themselves teach Qigong, Tai Chi, and Kung fu in harmony with eachother. This comes from first hand experience while training in China. Plus Tai Chi has it's roots on Wudang mountain.
I have been down this road before waaaaaay to many times but I do not agree.
True Yang style by itself if trained correctly is very effective as a martial art. The real problem with Yang style is that there are so few real teachers out there teaching it and a whole lot of people calling what they do Yang style when it is in effect not or not traditional or neutered of its Martial arts roots. Or worse you get someone that has trained a hard style and combines it with Yang and calls it Yang style martial arts. I have seen this too and it is way to tense and not anywhere near as relaxed as it should be.
I have trained Yang for 12 years and I know it is effective, most unfortunately I have also had to use it as a martial art out in the real world. I have also trained other styles but the most recent and the longest is Yang and I will admit it is not my favorite Tai Chi style, Chen is but I have to say real Yang style is very effective all by itself as a martial art.
If you are lucky enough to find a true Yang style sifu, believe me it is very effective, I have had 2 throw me around like a rag doll and one almost rip me in two pieces over the years. My sifu is from China and he was a student of Tung Ying Chieh. Also Cheng Manching style as taught by William CC Chen is very effective, by itself as a martial art.
As to Tai Chi roots on Wudang Mountain, it depends on whom you talk to; there are at least 3 or 4 roots and or lineages thrown around. According to the Chen family it has its roots with them and the Wudang mountain story is a myth. The only connection to Wudang is the Chen family founder also studied Taoism.
Also you must take into account that Yang comes directly from Chen and it was very effective then and all the way up to Yang Chengfu and his students and his students students who now teach some of us, if we're lucky.
As to training in China, I have been there as well and I will say what I saw of Yang style was rather badly done but what I saw was 24 form. Most unfortunately the only traditional I saw was 3 older gentlemen as they finished the very last 3 postures. I also saw Wu style, Sun Style and Chen done very very well.
If I may ask, how long did you train at Wudang?