https://www.marketindex.com.au/methodologyFor ASX200 (also same...

https://www.marketindex.com.au/methodology

For ASX200 (also same criteria used for ASX300):
"Selection CriteriaA security must be listed on the ASX and be an ordinary or preferred equity stock (e.g. no bonds or warrants etc.). Its average daily market capitalisation for the previous six months must be considered institutionally investable and meet a minimum benchmark size. Liquidity must be adequate and its public float (shares not owned by company founders, directors, government agencies etc.) must also meet a minimum requirement.Note: The above criteria are for inclusion into the index and not for continued membership. As low index turnover is important, a security in the index may on occasions violate one or more of the selection criteria without being removed."

My take away is that it is not able to be included in ASX300 indices as the price rise has only been a recent development.

For the XAO however
"The constituents are simply the 500 largest companies listed on the ASX by way of market capitalisation. Unlike the S&P/ASX suite of indices, the All Ordinaries has no liquidity requirement.The market capitalisation of a company is calculated by multiplying its share price by the number of shares currently held by the public. This value is then used to assign a percentage ‘weight’ for that company. Once all the stocks in an index have been ‘weighted’, the All Ordinaries is calculated by adding together all the ‘weighted’ values, then dividing the sum by the total number of companies that comprise the index."

My interpretation seems to point that it will be included in XAO indices, which rebalances on the third Friday of March.