Technically, yes.
They will not just ask your mum outright questions like can you remember if he/she sustained attention etc. They will also ask questions about how you played, etc. They try and get the information they need in ways other than just asking leading questions, however the technicality part of it comes down to whether or not they can get that information, and it might be much easier for you to find somebody else who knew you from childhood to give this information, or dig out old school reports.
A lot of people go to assessments with non-cooperative parents or non-understanding parents, but still manage to walk away with an ADHD diagnosis.
I went to my assessment with a 5 page essay listing all the things I remember from early childhood, including in my reception class, where I would frequently be called upon to answer questions, and burst out crying because I realised I hadn't been paying attention again, and had been intentionally called upon to answer the question again because the teacher realised I was away with the fairies, as some sort of punitive measure, all the way up to high school where I would set off early for the bus (7am, when the bus came at 8am and I lived 2 minutes away from the bus stop), just so I wouldn't miss the bus, and somehow I would still not be paying attention, not be able to put my arm out for the bus, and would miss the bus anyway, to high school missing that I was unable to sustain attention with my assignments, because I would forget they exist and then at 2am, I'd be up writing 2000 word essays just to submit them on time.
When I was about 10, I remember going to my friends May Queen celebration at church and I had to sit next to her in this fancy gown, and everybody was told to get up while we sung a hymn, and I realised half way through the hymn that I was staring at the eaves, not singing and still sat down, and everybody was staring at me.
I wrote about how at bedtimes, I can never just get in bed and go to sleep, it's like I have a thousand ideas that I need to do right now, and how as a child my mum would have to come and tell me to get back in bed because I would get out of bed to play, or draw a picture, or write in my notepad, and it felt like I just couldn't rest until I'd done what I needed to do, and how once I'd started, I found it next to impossible to stop.
I wrote about how my room was always a mess, unless somebody was coming over and then I'd speed clean it, but otherwise I would have doom piles, where I knew where the things I needed were, but I just could not remain organised enough to put them away, and I'm still like this to this day. I attached photos of my current bedroom, and my mum confirmed that is exactly what my room was like as a child unless she cleaned my room for me, and how she used to get on at me for not being clean and tidy.
I think if they'd simply asked my mum outright for this information, she'd have said I was a normal child and she didn't notice anything out of the ordinary, because I don't think teachers really relayed this information to her, and she wasn't present for the missing of the school buses, and she wasn't present in church as we're not church goers, I was just there supporting my friend, but the OT doing my assessment along with the psychiatrist said that I had provided detailed accounts of my own personal history so they were able to get what else they needed from my mum by asking questions in a specific way to get the information they needed.