Short answer: I don't know.
Long answer: Oud Mostafa No 5 was procured from an ooold Cambodian artisan whose work I have tremendous respect for. Like Oud Yusuf and Assam Organic, I didn't distill the oil with my own hands. But the artisan and I see eye to eye on most aspects of distillation, and it is a lot more exciting for me to collaborate with such an old timer – every now and then – than to source the raw materials from him and distill my own oil. (It's not like I was distilling the next Vietnam Kinam, anyway...)
Longer answer: Inoculants have a smell. The age of trees, too, has a 'smell'. The age of the infection, too, 'smells' a certain way. I am certain no inoculants were used, because I trust this craftsman, and most importantly I don't smell any inoculants. To me, the trees 'smell' like they were between 15-20 years (closer to 15), and the infection 'smells' like it was between 2-3 years.
Bottom line: The age of the trees, the age of the infection, the 'blackness' of the raw materials mean very little to me. (Although the absence of inoculants means a great deal.) What I care about is the finished work. The end result. The question I ask is: Was the distiller able to take the raw materials and create something far beyond the average potential of such raw materials? In the case of Mostafa No 5, the answer was a resounding: YES!
Talking of the 'innate potential' of raw materials.... Someone showed up with a bunch of oils at the London OudFest from several online vendors. He was keen to get my opinion of them, so we started testing them one by one. At first, my first pick would have been a Sri Lankan oil which was distilled from high grade and costly raw materials. As we went through the samples back and forth, we ended up with four 'groups' of samples: the very low quality ones, the average ones, the good, and the very good ones.
Up to a certain point, the only 'very good' sample we had was this Sri Lankan oil; everything else was in the other categories. As the scents started to develop, I had to quickly put Adam's 'Old School Hindi' in the 'very good' pile, slightly ahead of the Sri Lankan oil even, although it was obviously distilled from cultivated raw materials, while the Sri Lankan was high grade wild. – The reason for this, as I explained to my guest, was because I clearly saw what Adam had done with that cultivated wood. He'd taken something of inherently low, or at best 'average' potential, and crafted something remarkable out of it. Whereas the Sri Lankan oil was a simple realization of that wood's potential. No matter how you distilled it, it would smell 'nice'.
Another guest showed up with samples of a purportedly wild Cambodian and an 'ultra aged' Kalimantan oil. The second I smelled the dipstick of the Cambodi bottle, I perched my lips, looked at Kruger and exclaimed: 'Tiem!' I couldn't help but point out the obvious. This oil was distilled from cultivated, inoculated, and very likely Thai agarwood. The 'inoculant note' in the scent was a dead giveaway. A dirty yellowness a the core that I can't help but point out the way I would DOP. Kruger took a whiff of it too (he's worked a lot more with cultivated wood than I have), and the verdict was unanimous: the oil was inoculated.
As for the super aged 'Kalimantan'..... we can leave that discussion for another time